server/postgres: support computed fields in order by

https://github.com/hasura/graphql-engine-mono/pull/1793 GitOrigin-RevId: e0396c0d4d96fc8f9bdbd7567193933db5b295a6
2024-12-14 17:02:49 +03:00 · 2021-07-27 21:57:28 +05:30 · 2021-07-27 21:57:28 +05:30 · 5cfac6ea87
commit 5cfac6ea87
parent e4155e4c5b
15 changed files with 348 additions and 136 deletions
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@ -3,6 +3,7 @@
 ## Next release
 (Add entries below in the order of server, console, cli, docs, others)

+- server: support computed fields in query 'order_by' (close #7103)
 - server: log warning if there are errors while executing clean up actions after "drop source" (previously it would throw an error) 
 - server: Fixed a bug where MSSQL and BigQuery would ignore environment variables set from the console
 - server: Fixing bug in ReplaceMetadata parser - Moving from Alternative to committed-choice.
--- a/server/src-lib/Hasura/Backends/BigQuery/FromIr.hs
+++ b/server/src-lib/Hasura/Backends/BigQuery/FromIr.hs
@ -403,7 +403,7 @@ fromSelectArgsG selectArgsG = do
      Nothing -> pure Proxy
      Just {} -> refute (pure DistinctIsn'tSupported)
  (argsOrderBy, joins) <-
-    runWriterT (traverse fromAnnOrderByItemG (maybe [] toList orders))
+    runWriterT (traverse fromAnnotatedOrderByItemG (maybe [] toList orders))
  -- Any object-relation joins that we generated, we record their
  -- generated names into a mapping.
  let argsExistingJoins =
@ -424,10 +424,10 @@ fromSelectArgsG selectArgsG = do

 -- | Produce a valid ORDER BY construct, telling about any joins
 -- needed on the side.
-fromAnnOrderByItemG ::
-     Ir.AnnOrderByItemG 'BigQuery Expression -> WriterT (Seq UnfurledJoin) (ReaderT EntityAlias FromIr) OrderBy
-fromAnnOrderByItemG Ir.OrderByItemG {obiType, obiColumn, obiNulls} = do
-  orderByFieldName <- unfurlAnnOrderByElement obiColumn
+fromAnnotatedOrderByItemG ::
+     Ir.AnnotatedOrderByItemG 'BigQuery Expression -> WriterT (Seq UnfurledJoin) (ReaderT EntityAlias FromIr) OrderBy
+fromAnnotatedOrderByItemG Ir.OrderByItemG {obiType, obiColumn, obiNulls} = do
+  orderByFieldName <- unfurlAnnotatedOrderByElement obiColumn
  let morderByOrder =
        obiType
  let orderByNullsOrder =
@ -439,9 +439,9 @@ fromAnnOrderByItemG Ir.OrderByItemG {obiType, obiColumn, obiNulls} = do
 -- | Unfurl the nested set of object relations (tell'd in the writer)
 -- that are terminated by field name (Ir.AOCColumn and
 -- Ir.AOCArrayAggregation).
-unfurlAnnOrderByElement ::
-     Ir.AnnOrderByElement 'BigQuery Expression -> WriterT (Seq UnfurledJoin) (ReaderT EntityAlias FromIr) FieldName
-unfurlAnnOrderByElement =
+unfurlAnnotatedOrderByElement ::
+     Ir.AnnotatedOrderByElement 'BigQuery Expression -> WriterT (Seq UnfurledJoin) (ReaderT EntityAlias FromIr) FieldName
+unfurlAnnotatedOrderByElement =
  \case
    Ir.AOCColumn pgColumnInfo -> lift (fromPGColumnInfo pgColumnInfo)
    Ir.AOCObjectRelation Rql.RelInfo {riMapping = mapping, riRTable = tableName} annBoolExp annOrderByElementG -> do
@ -477,7 +477,7 @@ unfurlAnnOrderByElement =
                   }
             , unfurledObjectTableAlias = Just (tableName, joinAliasEntity)
             })
-      local (const joinAliasEntity) (unfurlAnnOrderByElement annOrderByElementG)
+      local (const joinAliasEntity) (unfurlAnnotatedOrderByElement annOrderByElementG)
    Ir.AOCArrayAggregation Rql.RelInfo {riMapping = mapping, riRTable = tableName} annBoolExp annAggregateOrderBy -> do
      selectFrom <- lift (lift (fromQualifiedTable tableName))
      let alias = aggFieldName
--- a/server/src-lib/Hasura/Backends/MSSQL/FromIr.hs
+++ b/server/src-lib/Hasura/Backends/MSSQL/FromIr.hs
@ -358,7 +358,7 @@ fromSelectArgsG selectArgsG = do
  -- you can just drop the Proxy wrapper.
  let argsDistinct = Proxy
  (argsOrderBy, joins) <-
-    runWriterT (traverse fromAnnOrderByItemG (maybe [] toList orders))
+    runWriterT (traverse fromAnnotatedOrderByItemG (maybe [] toList orders))
  -- Any object-relation joins that we generated, we record their
  -- generated names into a mapping.
  let argsExistingJoins =
@ -378,11 +378,11 @@ fromSelectArgsG selectArgsG = do

 -- | Produce a valid ORDER BY construct, telling about any joins
 -- needed on the side.
-fromAnnOrderByItemG
-  :: IR.AnnOrderByItemG 'MSSQL Expression
+fromAnnotatedOrderByItemG
+  :: IR.AnnotatedOrderByItemG 'MSSQL Expression
  -> WriterT (Seq UnfurledJoin) (ReaderT EntityAlias FromIr) OrderBy
-fromAnnOrderByItemG IR.OrderByItemG {obiType, obiColumn = obiColumn, obiNulls} = do
-  (orderByFieldName, orderByType) <- unfurlAnnOrderByElement obiColumn
+fromAnnotatedOrderByItemG IR.OrderByItemG {obiType, obiColumn = obiColumn, obiNulls} = do
+  (orderByFieldName, orderByType) <- unfurlAnnotatedOrderByElement obiColumn
  let orderByNullsOrder = fromMaybe NullsAnyOrder obiNulls
      orderByOrder      = fromMaybe AscOrder obiType
  pure OrderBy {..}
@ -390,10 +390,10 @@ fromAnnOrderByItemG IR.OrderByItemG {obiType, obiColumn = obiColumn, obiNulls} =
 -- | Unfurl the nested set of object relations (tell'd in the writer)
 -- that are terminated by field name (IR.AOCColumn and
 -- IR.AOCArrayAggregation).
-unfurlAnnOrderByElement
-   :: IR.AnnOrderByElement 'MSSQL Expression
+unfurlAnnotatedOrderByElement
+   :: IR.AnnotatedOrderByElement 'MSSQL Expression
   -> WriterT (Seq UnfurledJoin) (ReaderT EntityAlias FromIr) (FieldName, Maybe TSQL.ScalarType)
-unfurlAnnOrderByElement =
+unfurlAnnotatedOrderByElement =
  \case
    IR.AOCColumn pgColumnInfo -> do
      fieldName <- lift (fromPGColumnInfo pgColumnInfo)
@ -444,7 +444,7 @@ unfurlAnnOrderByElement =
             })
      local
        (const (EntityAlias joinAliasEntity))
-        (unfurlAnnOrderByElement annOrderByElementG)
+        (unfurlAnnotatedOrderByElement annOrderByElementG)
    IR.AOCArrayAggregation IR.RelInfo {riMapping = mapping, riRTable = tableName} annBoolExp annAggregateOrderBy -> do
      selectFrom <- lift (lift (fromQualifiedTable tableName))
      let alias = aggFieldName
--- a/server/src-lib/Hasura/Backends/Postgres/Translate/Select.hs
+++ b/server/src-lib/Hasura/Backends/Postgres/Translate/Select.hs
@ -220,11 +220,11 @@ mkBaseTableColumnAlias :: Identifier -> PGCol -> Identifier
 mkBaseTableColumnAlias pfx pgColumn =
  pfx <> Identifier ".pg." <> toIdentifier pgColumn

-mkOrderByFieldName :: RelName -> FieldName
-mkOrderByFieldName relName =
-  FieldName $ relNameToTxt relName <> "." <> "order_by"
+mkOrderByFieldName :: ToTxt a => a -> FieldName
+mkOrderByFieldName name =
+  FieldName $ toTxt name <> "." <> "order_by"

-mkAggregateOrderByAlias :: AnnAggregateOrderBy ('Postgres pgKind) -> S.Alias
+mkAggregateOrderByAlias :: AnnotatedAggregateOrderBy ('Postgres pgKind) -> S.Alias
 mkAggregateOrderByAlias = (S.Alias . Identifier) . \case
  AAOCount         -> "count"
  AAOOp opText col -> opText <> "." <> getPGColTxt (pgiColumn col)
@ -284,7 +284,7 @@ withForceAggregation tyAnn e =
 mkAggregateOrderByExtractorAndFields
  :: forall pgKind
   . Backend ('Postgres pgKind)
-  => AnnAggregateOrderBy ('Postgres pgKind)
+  => AnnotatedAggregateOrderBy ('Postgres pgKind)
  -> (S.Extractor, AggregateFields ('Postgres pgKind))
 mkAggregateOrderByExtractorAndFields annAggOrderBy =
  case annAggOrderBy of
@ -309,7 +309,7 @@ mkAggregateOrderByExtractorAndFields annAggOrderBy =
    alias = Just $ mkAggregateOrderByAlias annAggOrderBy

 mkAnnOrderByAlias
-  :: Identifier -> FieldName -> SimilarArrayFields -> AnnOrderByElementG ('Postgres pgKind) v -> S.Alias
+  :: Identifier -> FieldName -> SimilarArrayFields -> AnnotatedOrderByElement ('Postgres pgKind) v -> S.Alias
 mkAnnOrderByAlias pfx parAls similarFields = \case
  AOCColumn pgColumnInfo ->
    let pgColumn = pgiColumn pgColumnInfo
@ -328,6 +328,14 @@ mkAnnOrderByAlias pfx parAls similarFields = \case
                 mkOrderByFieldName rn
        obAls = arrPfx <> Identifier "." <> toIdentifier (mkAggregateOrderByAlias aggOrderBy)
    in S.Alias obAls
+  AOCComputedField cfOrderBy ->
+    let fieldName = fromComputedField $ _cfobName cfOrderBy
+    in case _cfobOrderByElement cfOrderBy of
+      CFOBEScalar _ -> S.Alias $ mkComputedFieldTableAlias pfx fieldName
+      CFOBETableAggregation _ _ aggOrderBy ->
+        let cfPfx = mkComputedFieldTableAlias pfx fieldName
+            obAls = cfPfx <> Identifier "." <> toIdentifier (mkAggregateOrderByAlias aggOrderBy)
+        in S.Alias obAls

 processDistinctOnColumns
  :: Identifier
@ -349,7 +357,7 @@ mkSimilarArrayFields
  :: forall pgKind v
   . (Backend ('Postgres pgKind), Eq v)
  => AnnFieldsG ('Postgres pgKind) (Const Void) v
-  -> Maybe (NE.NonEmpty (AnnOrderByItemG ('Postgres pgKind) v))
+  -> Maybe (NE.NonEmpty (AnnotatedOrderByItemG ('Postgres pgKind) v))
  -> SimilarArrayFields
 mkSimilarArrayFields annFields maybeOrderBys =
  HM.fromList $ flip map allTuples $
@ -432,7 +440,7 @@ withWriteArrayRelation action =
  pure (out, (source, topExtractor, nodeExtractors))
  where
    updateJoinTree joinTree (source, topExtractor, nodeExtractors) =
-      let arraySelectNode = ArraySelectNode [topExtractor] $
+      let arraySelectNode = MultiRowSelectNode [topExtractor] $
                            SelectNode nodeExtractors joinTree
      in mempty{_jtArrayRelations = HM.singleton source arraySelectNode}

@ -450,24 +458,25 @@ withWriteArrayConnection action =
  pure (out, (source, topExtractor, nodeExtractors))
  where
    updateJoinTree joinTree (source, topExtractor, nodeExtractors) =
-      let arraySelectNode = ArraySelectNode [topExtractor] $
+      let arraySelectNode = MultiRowSelectNode [topExtractor] $
                            SelectNode nodeExtractors joinTree
      in mempty{_jtArrayConnections = HM.singleton source arraySelectNode}

 withWriteComputedFieldTableSet
  :: (MonadWriter JoinTree m)
  => m ( ComputedFieldTableSetSource
+       , S.Extractor
       , HM.HashMap S.Alias S.SQLExp
       , a
       )
  -> m a
 withWriteComputedFieldTableSet action =
  withWriteJoinTree updateJoinTree $ do
-    (source, nodeExtractors, out) <- action
-    pure (out, (source, nodeExtractors))
+    (source, topExtractor, nodeExtractors, out) <- action
+    pure (out, (source, topExtractor, nodeExtractors))
  where
-    updateJoinTree joinTree (source, nodeExtractors) =
-      let selectNode = SelectNode nodeExtractors joinTree
+    updateJoinTree joinTree (source, topExtractor, nodeExtractors) =
+      let selectNode = MultiRowSelectNode [topExtractor] $ SelectNode nodeExtractors joinTree
      in mempty{_jtComputedFieldTableSets = HM.singleton source selectNode}


@ -557,7 +566,7 @@ processAnnAggregateSelect sourcePrefixes fieldAlias annAggSel = do
 mkPermissionLimitSubQuery
  :: Maybe Int
  -> TableAggregateFields ('Postgres pgKind)
-  -> Maybe (NE.NonEmpty (AnnOrderByItem ('Postgres pgKind)))
+  -> Maybe (NE.NonEmpty (AnnotatedOrderByItem ('Postgres pgKind)))
  -> PermissionLimitSubQuery
 mkPermissionLimitSubQuery permLimit aggFields orderBys =
  case permLimit of
@ -685,7 +694,7 @@ processOrderByItems
  => Identifier
  -> FieldName
  -> SimilarArrayFields
-  -> NE.NonEmpty (AnnOrderByItem ('Postgres pgKind))
+  -> NE.NonEmpty (AnnotatedOrderByItem ('Postgres pgKind))
  -> m ( [(S.Alias, S.SQLExp)] -- Order by Extractors
       , S.OrderByExp
       , S.SQLExp -- The cursor expression
@ -698,15 +707,15 @@ processOrderByItems sourcePrefix' fieldAlias' similarArrayFields orderByItems =
  pure (orderByExtractors, orderByExp, cursor)
  where
    processAnnOrderByItem
-      :: AnnOrderByItem ('Postgres pgKind)
-      -> m (OrderByItemG ('Postgres pgKind) (AnnOrderByElement ('Postgres pgKind) (SQLExpression ('Postgres pgKind)), (S.Alias, SQLExpression ('Postgres pgKind))))
+      :: AnnotatedOrderByItem ('Postgres pgKind)
+      -> m (OrderByItemG ('Postgres pgKind) (AnnotatedOrderByElement ('Postgres pgKind) (SQLExpression ('Postgres pgKind)), (S.Alias, SQLExpression ('Postgres pgKind))))
    processAnnOrderByItem orderByItem =
      forM orderByItem $ \ordByCol -> (ordByCol,) <$>
-      processAnnOrderByElement sourcePrefix' fieldAlias' ordByCol
+      processAnnotatedOrderByElement sourcePrefix' fieldAlias' ordByCol

-    processAnnOrderByElement
-      :: Identifier -> FieldName -> AnnOrderByElement ('Postgres pgKind) S.SQLExp -> m (S.Alias, S.SQLExp)
-    processAnnOrderByElement sourcePrefix fieldAlias annObCol = do
+    processAnnotatedOrderByElement
+      :: Identifier -> FieldName -> AnnotatedOrderByElement ('Postgres pgKind) S.SQLExp -> m (S.Alias, S.SQLExp)
+    processAnnotatedOrderByElement sourcePrefix fieldAlias annObCol = do
      let ordByAlias = mkAnnOrderByAlias sourcePrefix fieldAlias similarArrayFields annObCol
      (ordByAlias, ) <$> case annObCol of
        AOCColumn pgColInfo -> pure $
@ -717,7 +726,7 @@ processOrderByItems sourcePrefix' fieldAlias' similarArrayFields orderByItems =
              relSourcePrefix = mkObjectRelationTableAlias sourcePrefix relName
              fieldName = mkOrderByFieldName relName
          (relOrderByAlias, relOrdByExp) <-
-            processAnnOrderByElement relSourcePrefix fieldName rest
+            processAnnotatedOrderByElement relSourcePrefix fieldName rest
          let selectSource = ObjectSelectSource relSourcePrefix
                             (S.FISimple relTable Nothing)
                             (toSQLBoolExp (S.QualTable relTable) relFilter)
@ -745,15 +754,38 @@ processOrderByItems sourcePrefix' fieldAlias' similarArrayFields orderByItems =
               , S.mkQIdenExp relSourcePrefix (mkAggregateOrderByAlias aggOrderBy)
               )

+        AOCComputedField ComputedFieldOrderBy{..} ->
+          case _cfobOrderByElement of
+            CFOBEScalar _                                          -> do
+              let functionArgs = fromTableRowArgs sourcePrefix _cfobFunctionArgsExp
+                  functionExp  = S.FunctionExp _cfobFunction functionArgs Nothing
+              pure $ S.SEFunction functionExp
+            CFOBETableAggregation _ tableFilter aggOrderBy -> withWriteComputedFieldTableSet $ do
+              let fieldName = mkOrderByFieldName _cfobName
+                  computedFieldSourcePrefix = mkComputedFieldTableAlias sourcePrefix fieldName
+                  (topExtractor, fields) = mkAggregateOrderByExtractorAndFields aggOrderBy
+                  fromItem = selectFromToFromItem sourcePrefix $
+                             FromFunction _cfobFunction _cfobFunctionArgsExp Nothing
+                  functionQual = S.QualifiedIdentifier (functionToIdentifier _cfobFunction) Nothing
+                  selectSource = SelectSource computedFieldSourcePrefix fromItem Nothing
+                                 (toSQLBoolExp functionQual tableFilter)
+                                 Nothing Nothing Nothing
+                  source = ComputedFieldTableSetSource fieldName selectSource
+              pure ( source
+                   , topExtractor
+                   , HM.fromList $ aggregateFieldsToExtractorExps computedFieldSourcePrefix fields
+                   , S.mkQIdenExp computedFieldSourcePrefix (mkAggregateOrderByAlias aggOrderBy)
+                   )
+
    toOrderByExp
-      :: OrderByItemG ('Postgres pgKind) (AnnOrderByElement ('Postgres pgKind) (SQLExpression ('Postgres pgKind)), (S.Alias, SQLExpression ('Postgres pgKind)))
+      :: OrderByItemG ('Postgres pgKind) (AnnotatedOrderByElement ('Postgres pgKind) (SQLExpression ('Postgres pgKind)), (S.Alias, SQLExpression ('Postgres pgKind)))
      -> S.OrderByItem
    toOrderByExp orderByItemExp =
      let OrderByItemG obTyM expAlias obNullsM = fst . snd <$> orderByItemExp
      in S.OrderByItem (S.SEIdentifier $ toIdentifier expAlias) obTyM obNullsM

    mkCursorExp
-      :: [OrderByItemG ('Postgres pgKind) (AnnOrderByElement ('Postgres pgKind) (SQLExpression ('Postgres pgKind)), (S.Alias, SQLExpression ('Postgres pgKind)))]
+      :: [OrderByItemG ('Postgres pgKind) (AnnotatedOrderByElement ('Postgres pgKind) (SQLExpression ('Postgres pgKind)), (S.Alias, SQLExpression ('Postgres pgKind)))]
      -> S.SQLExp
    mkCursorExp orderByItemExps =
      S.applyJsonBuildObj $ flip concatMap orderByItemExps $
@ -761,6 +793,13 @@ processOrderByItems sourcePrefix' fieldAlias' similarArrayFields orderByItems =
        let OrderByItemG _ (annObCol, (_, valExp)) _ = orderByItemExp
        in annObColToJSONField valExp annObCol
      where
+        mkAggOrderByValExp valExp = \case
+          AAOCount -> [S.SELit "count", valExp]
+          AAOOp opText colInfo ->
+            [ S.SELit opText
+            , S.applyJsonBuildObj [S.SELit $ getPGColTxt $ pgiColumn colInfo, valExp]
+            ]
+
        annObColToJSONField valExp = \case
          AOCColumn pgCol -> [S.SELit $ getPGColTxt $ pgiColumn pgCol, valExp]
          AOCObjectRelation relInfo _ obCol ->
@ -769,14 +808,16 @@ processOrderByItems sourcePrefix' fieldAlias' similarArrayFields orderByItems =
            ]
          AOCArrayAggregation relInfo _ aggOrderBy ->
            [ S.SELit $ relNameToTxt (riName relInfo) <> "_aggregate"
-            , S.applyJsonBuildObj $
-              case aggOrderBy of
-                AAOCount -> [S.SELit "count", valExp]
-                AAOOp opText colInfo ->
-                  [ S.SELit opText
-                  , S.applyJsonBuildObj [S.SELit $ getPGColTxt $ pgiColumn colInfo, valExp]
-                  ]
+            , S.applyJsonBuildObj $ mkAggOrderByValExp valExp aggOrderBy
            ]
+          AOCComputedField cfOrderBy ->
+            let fieldNameText = computedFieldNameToText $ _cfobName cfOrderBy
+            in case _cfobOrderByElement cfOrderBy of
+                 CFOBEScalar _ -> [S.SELit fieldNameText, valExp]
+                 CFOBETableAggregation _ _ aggOrderBy ->
+                   [ S.SELit $ fieldNameText <> "_aggregate"
+                   , S.applyJsonBuildObj $ mkAggOrderByValExp valExp aggOrderBy
+                   ]

 aggregateFieldsToExtractorExps
  :: Identifier -> AggregateFields ('Postgres pgKind) -> [(S.Alias, S.SQLExp)]
@ -917,9 +958,11 @@ processAnnFields sourcePrefix fieldAlias similarArrFields annFields = do
        (selectSource, nodeExtractors) <-
          processAnnSimpleSelect (mkSourcePrefixes computedFieldSourcePrefix)
          fieldName PLSQNotRequired sel
-        let computedFieldTableSetSource =
-              ComputedFieldTableSetSource fieldName selectTy selectSource
+        let computedFieldTableSetSource = ComputedFieldTableSetSource fieldName selectSource
+            extractor = asJsonAggExtr selectTy (S.toAlias fieldName) PLSQNotRequired $
+                        _ssOrderBy selectSource
        pure ( computedFieldTableSetSource
+             , extractor
             , nodeExtractors
             , S.mkQIdenExp computedFieldSourcePrefix fieldName
             )
@ -1027,7 +1070,6 @@ generateSQLSelect joinCondition selectSource selectNode =
                 map arrayConnectionToFromItem (HM.toList arrayConnections) <>
                 map computedFieldToFromItem (HM.toList computedFields)

-
    objectRelationToFromItem
      :: (ObjectRelationSource, SelectNode) -> S.FromItem
    objectRelationToFromItem (objectRelationSource, node) =
@ -1038,7 +1080,7 @@ generateSQLSelect joinCondition selectSource selectNode =
      in S.mkLateralFromItem select alias

    arrayRelationToFromItem
-      :: (ArrayRelationSource, ArraySelectNode) -> S.FromItem
+      :: (ArrayRelationSource, MultiRowSelectNode) -> S.FromItem
    arrayRelationToFromItem (arrayRelationSource, arraySelectNode) =
      let ArrayRelationSource _ colMapping source = arrayRelationSource
          alias = S.Alias $ _ssPrefix source
@ -1047,29 +1089,27 @@ generateSQLSelect joinCondition selectSource selectNode =
      in S.mkLateralFromItem select alias

    arrayConnectionToFromItem
-      :: (ArrayConnectionSource, ArraySelectNode) -> S.FromItem
+      :: (ArrayConnectionSource, MultiRowSelectNode) -> S.FromItem
    arrayConnectionToFromItem (arrayConnectionSource, arraySelectNode) =
      let selectWith = connectionToSelectWith baseSelectAlias arrayConnectionSource arraySelectNode
          alias = S.Alias $ _ssPrefix $ _acsSource arrayConnectionSource
      in S.FISelectWith (S.Lateral True) selectWith alias

    computedFieldToFromItem
-      :: (ComputedFieldTableSetSource, SelectNode) -> S.FromItem
+      :: (ComputedFieldTableSetSource, MultiRowSelectNode) -> S.FromItem
    computedFieldToFromItem (computedFieldTableSource, node) =
-      let ComputedFieldTableSetSource fieldName selectTy source = computedFieldTableSource
-          internalSelect = generateSQLSelect (S.BELit True) source node
-          extractor = asJsonAggExtr selectTy (S.toAlias fieldName) PLSQNotRequired $
-                      _ssOrderBy source
+      let ComputedFieldTableSetSource _ source = computedFieldTableSource
+          internalSelect = generateSQLSelect (S.BELit True) source $ _mrsnSelectNode node
          alias = S.Alias $ _ssPrefix source
          select = S.mkSelect
-                { S.selExtr = [extractor]
+                { S.selExtr = _mrsnTopExtractors node
                , S.selFrom = Just $ S.FromExp [S.mkSelFromItem internalSelect alias]
                }
      in S.mkLateralFromItem select alias

 generateSQLSelectFromArrayNode
  :: SelectSource
-  -> ArraySelectNode
+  -> MultiRowSelectNode
  -> S.BoolExp
  -> S.Select
 generateSQLSelectFromArrayNode selectSource arraySelectNode joinCondition =
@ -1078,7 +1118,7 @@ generateSQLSelectFromArrayNode selectSource arraySelectNode joinCondition =
  , S.selFrom = Just $ S.FromExp [selectFrom]
  }
  where
-    ArraySelectNode topExtractors selectNode = arraySelectNode
+    MultiRowSelectNode topExtractors selectNode = arraySelectNode
    selectFrom = S.mkSelFromItem
                 (generateSQLSelect joinCondition selectSource selectNode) $
                 S.Alias $ _ssPrefix selectSource
@ -1095,7 +1135,7 @@ mkAggregateSelect annAggSel =
        runWriter $ flip runReaderT strfyNum $
        processAnnAggregateSelect sourcePrefixes rootFieldName annAggSel
      selectNode = SelectNode nodeExtractors joinTree
-      arrayNode = ArraySelectNode [topExtractor] selectNode
+      arrayNode = MultiRowSelectNode [topExtractor] selectNode
  in prefixNumToAliases $
     generateSQLSelectFromArrayNode selectSource arrayNode $ S.BELit True
  where
@ -1120,7 +1160,7 @@ mkSQLSelect jsonAggSelect annSel =
      selectNode = SelectNode nodeExtractors joinTree
      topExtractor = asJsonAggExtr jsonAggSelect rootFldAls permLimitSubQuery
                     $ _ssOrderBy selectSource
-      arrayNode = ArraySelectNode [topExtractor] selectNode
+      arrayNode = MultiRowSelectNode [topExtractor] selectNode
  in prefixNumToAliases $
     generateSQLSelectFromArrayNode selectSource arrayNode $ S.BELit True
  where
@ -1142,7 +1182,7 @@ mkConnectionSelect connectionSelect =
        runWriter $ flip runReaderT strfyNum $
        processConnectionSelect sourcePrefixes rootFieldName
        (S.Alias rootIdentifier) mempty connectionSelect
-      selectNode = ArraySelectNode [topExtractor] $
+      selectNode = MultiRowSelectNode [topExtractor] $
                       SelectNode nodeExtractors joinTree
  in prefixNumToAliasesSelectWith $
     connectionToSelectWith (S.Alias rootIdentifier) connectionSource selectNode
@ -1350,7 +1390,7 @@ processConnectionSelect sourcePrefixes fieldAlias relAlias colMapping connection
 connectionToSelectWith
  :: S.Alias
  -> ArrayConnectionSource
-  -> ArraySelectNode
+  -> MultiRowSelectNode
  -> S.SelectWithG S.Select
 connectionToSelectWith baseSelectAlias arrayConnectionSource arraySelectNode =
  let extractionSelect = S.mkSelect
@ -1361,7 +1401,7 @@ connectionToSelectWith baseSelectAlias arrayConnectionSource arraySelectNode =
  where
    ArrayConnectionSource _ columnMapping maybeSplit maybeSlice selectSource =
      arrayConnectionSource
-    ArraySelectNode topExtractors selectNode = arraySelectNode
+    MultiRowSelectNode topExtractors selectNode = arraySelectNode
    baseSelectIdentifier = Identifier "__base_select"
    splitSelectIdentifier = Identifier "__split_select"
    sliceSelectIdentifier = Identifier "__slice_select"
--- a/server/src-lib/Hasura/Backends/Postgres/Translate/Types.hs
+++ b/server/src-lib/Hasura/Backends/Postgres/Translate/Types.hs
@ -79,20 +79,19 @@ data ArrayRelationSource
 instance Hashable ArrayRelationSource
 deriving instance Eq ArrayRelationSource

-data ArraySelectNode
-  = ArraySelectNode
-  { _asnTopExtractors :: ![PG.Extractor]
-  , _asnSelectNode    :: !SelectNode
+data MultiRowSelectNode
+  = MultiRowSelectNode
+  { _mrsnTopExtractors :: ![PG.Extractor]
+  , _mrsnSelectNode    :: !SelectNode
  }

-instance Semigroup ArraySelectNode where
-  ArraySelectNode lTopExtrs lSelNode <> ArraySelectNode rTopExtrs rSelNode =
-    ArraySelectNode (lTopExtrs <> rTopExtrs) (lSelNode <> rSelNode)
+instance Semigroup MultiRowSelectNode where
+  MultiRowSelectNode lTopExtrs lSelNode <> MultiRowSelectNode rTopExtrs rSelNode =
+    MultiRowSelectNode (lTopExtrs <> rTopExtrs) (lSelNode <> rSelNode)

 data ComputedFieldTableSetSource
  = ComputedFieldTableSetSource
  { _cftssFieldName    :: !FieldName
-  , _cftssSelectType   :: !JsonAggSelect
  , _cftssSelectSource :: !SelectSource
  } deriving (Generic)
 instance Hashable ComputedFieldTableSetSource
@ -114,9 +113,9 @@ instance Hashable ArrayConnectionSource
 data JoinTree
  = JoinTree
  { _jtObjectRelations        :: !(HM.HashMap ObjectRelationSource SelectNode)
-  , _jtArrayRelations         :: !(HM.HashMap ArrayRelationSource ArraySelectNode)
-  , _jtArrayConnections       :: !(HM.HashMap ArrayConnectionSource ArraySelectNode)
-  , _jtComputedFieldTableSets :: !(HM.HashMap ComputedFieldTableSetSource SelectNode)
+  , _jtArrayRelations         :: !(HM.HashMap ArrayRelationSource MultiRowSelectNode)
+  , _jtArrayConnections       :: !(HM.HashMap ArrayConnectionSource MultiRowSelectNode)
+  , _jtComputedFieldTableSets :: !(HM.HashMap ComputedFieldTableSetSource MultiRowSelectNode)
  }

 instance Semigroup JoinTree where
--- a/server/src-lib/Hasura/GraphQL/Execute/RemoteJoin/Collect.hs
+++ b/server/src-lib/Hasura/GraphQL/Execute/RemoteJoin/Collect.hs
@ -322,19 +322,10 @@ transformAnnFields path fields = do
    mkScalarComputedFieldSelect :: ScalarComputedField b -> (AnnFieldG b (Const Void) (UnpreparedValue b))
    mkScalarComputedFieldSelect ScalarComputedField{..} =
      let functionArgs = flip FunctionArgsExp mempty
-            $ functionArgsWithTableRowAndSession _scfTableArgument _scfSessionArgument
+            $ functionArgsWithTableRowAndSession UVSession _scfTableArgument _scfSessionArgument
          fieldSelect = flip CFSScalar Nothing
            $ ComputedFieldScalarSelect _scfFunction functionArgs _scfType Nothing
      in AFComputedField _scfXField _scfName fieldSelect
-      where
-        functionArgsWithTableRowAndSession
-          :: FunctionTableArgument
-          -> Maybe FunctionSessionArgument
-          -> [ArgumentExp b (UnpreparedValue b)]
-        functionArgsWithTableRowAndSession  _              Nothing = [AETableRow Nothing] -- No session argument
-        functionArgsWithTableRowAndSession  (FTAFirst)     _       = [AETableRow Nothing, AESession UVSession]
-        functionArgsWithTableRowAndSession  (FTANamed _ 0) _       = [AETableRow Nothing, AESession UVSession] -- Index is 0 implies table argument is first
-        functionArgsWithTableRowAndSession  _              _       = [AESession UVSession, AETableRow Nothing]


 mapToNonEmpty :: RemoteJoinMap -> Maybe RemoteJoins
--- a/server/src-lib/Hasura/GraphQL/Schema/OrderBy.hs
+++ b/server/src-lib/Hasura/GraphQL/Schema/OrderBy.hs
@ -36,7 +36,7 @@ orderByExp
  => SourceName
  -> TableInfo b
  -> SelPermInfo b
-  -> m (Parser 'Input n [IR.AnnOrderByItemG b (UnpreparedValue b)])
+  -> m (Parser 'Input n [IR.AnnotatedOrderByItemG b (UnpreparedValue b)])
 orderByExp sourceName tableInfo selectPermissions = memoizeOn 'orderByExp (sourceName, tableInfoName tableInfo) $ do
  tableGQLName <- getTableGQLName tableInfo
  let name = tableGQLName <> $$(G.litName "_order_by")
@ -48,18 +48,19 @@ orderByExp sourceName tableInfo selectPermissions = memoizeOn 'orderByExp (sourc
  where
    mkField
      :: FieldInfo b
-      -> m (Maybe (InputFieldsParser n (Maybe [IR.AnnOrderByItemG b (UnpreparedValue b)])))
+      -> m (Maybe (InputFieldsParser n (Maybe [IR.AnnotatedOrderByItemG b (UnpreparedValue b)])))
    mkField fieldInfo = runMaybeT $
      case fieldInfo of
        FIColumn columnInfo -> do
          let fieldName = pgiName columnInfo
          pure $ P.fieldOptional fieldName Nothing (orderByOperator @b)
            <&> fmap (pure . mkOrderByItemG @b (IR.AOCColumn columnInfo)) . join
+
        FIRelationship relationshipInfo -> do
          remoteTableInfo <- askTableInfo @b sourceName $ riRTable relationshipInfo
          fieldName <- hoistMaybe $ G.mkName $ relNameToTxt $ riName relationshipInfo
          perms <- MaybeT $ tableSelectPermissions remoteTableInfo
-          let newPerms = (fmap . fmap) partialSQLExpToUnpreparedValue $ spiFilter perms
+          let newPerms = fmap partialSQLExpToUnpreparedValue <$> spiFilter perms
          case riType relationshipInfo of
            ObjRel -> do
              otherTableParser <- lift $ orderByExp sourceName remoteTableInfo perms
@ -72,7 +73,33 @@ orderByExp sourceName tableInfo selectPermissions = memoizeOn 'orderByExp (sourc
              pure $ do
                aggregationOrderBy <- join <$> P.fieldOptional aggregateFieldName Nothing (P.nullable aggregationParser)
                pure $ fmap (map $ fmap $ IR.AOCArrayAggregation relationshipInfo newPerms) aggregationOrderBy
-        FIComputedField _ -> empty
+
+        FIComputedField ComputedFieldInfo{..} -> do
+          let ComputedFieldFunction{..} = _cfiFunction
+              mkComputedFieldOrderBy =
+                let functionArgs = flip IR.FunctionArgsExp mempty
+                      $ IR.functionArgsWithTableRowAndSession P.UVSession _cffTableArgument _cffSessionArgument
+                in IR.ComputedFieldOrderBy _cfiXComputedFieldInfo _cfiName _cffName functionArgs
+          fieldName <- hoistMaybe $ G.mkName $ toTxt _cfiName
+          guard $ _cffInputArgs == mempty -- No input arguments other than table row and session argument
+          case _cfiReturnType of
+            CFRScalar scalarType -> do
+              let computedFieldOrderBy = mkComputedFieldOrderBy $ IR.CFOBEScalar scalarType
+              pure $ P.fieldOptional fieldName Nothing (orderByOperator @b)
+                <&> fmap (pure . mkOrderByItemG @b (IR.AOCComputedField computedFieldOrderBy)) . join
+            CFRSetofTable table -> do
+              let aggregateFieldName = fieldName <> $$(G.litName "_aggregate")
+              tableInfo' <- askTableInfo @b sourceName table
+              perms <- MaybeT $ tableSelectPermissions tableInfo'
+              let newPerms = fmap partialSQLExpToUnpreparedValue <$> spiFilter perms
+              aggregationParser <- lift $ orderByAggregation sourceName tableInfo' perms
+              pure $ do
+                aggregationOrderBy <- join <$> P.fieldOptional aggregateFieldName Nothing (P.nullable aggregationParser)
+                pure $ fmap (map $ fmap $ IR.AOCComputedField
+                             . mkComputedFieldOrderBy
+                             . IR.CFOBETableAggregation table newPerms
+                            ) aggregationOrderBy
+
        FIRemoteRelationship _ -> empty


@ -85,7 +112,7 @@ orderByAggregation
  => SourceName
  -> TableInfo b
  -> SelPermInfo b
-  -> m (Parser 'Input n [IR.OrderByItemG b (IR.AnnAggregateOrderBy b)])
+  -> m (Parser 'Input n [IR.OrderByItemG b (IR.AnnotatedAggregateOrderBy b)])
 orderByAggregation sourceName tableInfo selectPermissions = memoizeOn 'orderByAggregation (sourceName, tableName) do
  -- WIP NOTE
  -- there is heavy duplication between this and Select.tableAggregationFields
@ -125,7 +152,7 @@ orderByAggregation sourceName tableInfo selectPermissions = memoizeOn 'orderByAg
      :: G.Name
      -> G.Name
      -> InputFieldsParser n [(ColumnInfo b, (BasicOrderType b, NullsOrderType b))]
-      -> InputFieldsParser n (Maybe [IR.OrderByItemG b (IR.AnnAggregateOrderBy b)])
+      -> InputFieldsParser n (Maybe [IR.OrderByItemG b (IR.AnnotatedAggregateOrderBy b)])
    parseOperator operator tableGQLName columns =
      let opText     = G.unName operator
          objectName = tableGQLName <> $$(G.litName "_") <> operator <> $$(G.litName "_order_by")
--- a/server/src-lib/Hasura/GraphQL/Schema/Select.hs
+++ b/server/src-lib/Hasura/GraphQL/Schema/Select.hs
@ -625,7 +625,7 @@ tableOrderByArg
  => SourceName
  -> TableInfo b
  -> SelPermInfo b
-  -> m (InputFieldsParser n (Maybe (NonEmpty (IR.AnnOrderByItemG b (UnpreparedValue b)))))
+  -> m (InputFieldsParser n (Maybe (NonEmpty (IR.AnnotatedOrderByItemG b (UnpreparedValue b)))))
 tableOrderByArg sourceName tableInfo selectPermissions = do
  orderByParser <- orderByExp sourceName tableInfo selectPermissions
  pure $ do
@ -738,7 +738,7 @@ tableConnectionArgs pkeyColumns sourceName tableInfo selectPermissions = do
  where
    base64Text = base64Decode <$> P.string

-    appendPrimaryKeyOrderBy :: NonEmpty (IR.AnnOrderByItemG b v) -> NonEmpty (IR.AnnOrderByItemG b v)
+    appendPrimaryKeyOrderBy :: NonEmpty (IR.AnnotatedOrderByItemG b v) -> NonEmpty (IR.AnnotatedOrderByItemG b v)
    appendPrimaryKeyOrderBy orderBys@(h NE.:| t) =
      let orderByColumnNames =
            orderBys ^.. traverse . to IR.obiColumn . IR._AOCColumn . to pgiColumn
@ -748,7 +748,7 @@ tableConnectionArgs pkeyColumns sourceName tableInfo selectPermissions = do
      in h NE.:| (t <> pkeyOrderBys)

    parseConnectionSplit
-      :: Maybe (NonEmpty (IR.AnnOrderByItemG b (UnpreparedValue b)))
+      :: Maybe (NonEmpty (IR.AnnotatedOrderByItemG b (UnpreparedValue b)))
      -> IR.ConnectionSplitKind
      -> BL.ByteString
      -> n (NonEmpty (IR.ConnectionSplit b (UnpreparedValue b)))
@ -774,11 +774,15 @@ tableConnectionArgs pkeyColumns sourceName tableInfo selectPermissions = do
            pgValue <- liftQErr $ parseScalarValueColumnType columnType orderByItemValue
            let unresolvedValue = UVParameter Nothing $ ColumnValue columnType pgValue
            pure $ IR.ConnectionSplit splitKind unresolvedValue $
-                   IR.OrderByItemG orderType (() <$ annObCol) nullsOrder
+                   IR.OrderByItemG orderType annObCol nullsOrder
      where
        throwInvalidCursor = parseError "the \"after\" or \"before\" cursor is invalid"
        liftQErr = either (parseError . qeError) pure . runExcept

+        mkAggregateOrderByPath = \case
+           IR.AAOCount    -> [J.Key "count"]
+           IR.AAOOp t col -> [J.Key t, J.Key $ toTxt $ pgiColumn col]
+
        getPathFromOrderBy = \case
          IR.AOCColumn pgColInfo ->
            let pathElement = J.Key $ toTxt $ pgiColumn pgColInfo
@ -788,15 +792,24 @@ tableConnectionArgs pkeyColumns sourceName tableInfo selectPermissions = do
            in pathElement : getPathFromOrderBy obCol
          IR.AOCArrayAggregation relInfo _ aggOb ->
            let fieldName = J.Key $ relNameToTxt (riName relInfo) <> "_aggregate"
-            in fieldName : case aggOb of
-                 IR.AAOCount    -> [J.Key "count"]
-                 IR.AAOOp t col -> [J.Key t, J.Key $ toTxt $ pgiColumn col]
+            in fieldName : mkAggregateOrderByPath aggOb
+          IR.AOCComputedField cfob ->
+            let fieldNameText = computedFieldNameToText $ IR._cfobName cfob
+            in case IR._cfobOrderByElement cfob of
+                 IR.CFOBEScalar _ -> [J.Key fieldNameText]
+                 IR.CFOBETableAggregation _ _ aggOb ->
+                   J.Key (fieldNameText <> "_aggregate") : mkAggregateOrderByPath aggOb

        getOrderByColumnType = \case
          IR.AOCColumn pgColInfo -> pgiType pgColInfo
          IR.AOCObjectRelation _ _ obCol -> getOrderByColumnType obCol
-          IR.AOCArrayAggregation _ _ aggOb ->
-            case aggOb of
+          IR.AOCArrayAggregation _ _ aggOb -> aggregateOrderByColumnType aggOb
+          IR.AOCComputedField cfob ->
+            case IR._cfobOrderByElement cfob of
+              IR.CFOBEScalar scalarType          -> ColumnScalar scalarType
+              IR.CFOBETableAggregation _ _ aggOb -> aggregateOrderByColumnType aggOb
+          where
+            aggregateOrderByColumnType = \case
              IR.AAOCount        -> ColumnScalar (aggregateOrderByCountType @b)
              IR.AAOOp _ colInfo -> pgiType colInfo

@ -1311,7 +1324,7 @@ functionArgs functionTrackedAs (toList -> inputArgs) = do

 tablePermissionsInfo :: Backend b => SelPermInfo b -> TablePerms b
 tablePermissionsInfo selectPermissions = IR.TablePerm
-  { IR._tpFilter = (fmap . fmap) partialSQLExpToUnpreparedValue $ spiFilter selectPermissions
+  { IR._tpFilter = fmap partialSQLExpToUnpreparedValue <$> spiFilter selectPermissions
  , IR._tpLimit  = spiLimit selectPermissions
  }

--- a/server/src-lib/Hasura/RQL/DML/Select.hs
+++ b/server/src-lib/Hasura/RQL/DML/Select.hs
@ -47,7 +47,7 @@ convSelCol
  -> SelCol
  -> m [ExtCol ('Postgres 'Vanilla)]
 convSelCol _ _ (SCExtSimple cn) =
-  return [ECSimple cn]
+  pure [ECSimple cn]
 convSelCol fieldInfoMap _ (SCExtRel rn malias selQ) = do
  -- Point to the name key
  let pgWhenRelErr = "only relationships can be expanded"
@ -56,7 +56,7 @@ convSelCol fieldInfoMap _ (SCExtRel rn malias selQ) = do
  let (RelInfo _ _ _ relTab _ _ _) = relInfo
  (rfim, rspi) <- fetchRelDet rn relTab
  resolvedSelQ <- resolveStar rfim rspi selQ
-  return [ECRel rn malias resolvedSelQ]
+  pure [ECRel rn malias resolvedSelQ]
 convSelCol fieldInfoMap spi (SCStar wildcard) =
  convWildcard fieldInfoMap spi wildcard

@ -68,7 +68,7 @@ convWildcard
  -> m [ExtCol ('Postgres 'Vanilla)]
 convWildcard fieldInfoMap selPermInfo wildcard =
  case wildcard of
-  Star         -> return simpleCols
+  Star         -> pure simpleCols
  (StarDot wc) -> (simpleCols ++) <$> (catMaybes <$> relExtCols wc)
  where
    cols = spiCols selPermInfo
@ -85,7 +85,7 @@ convWildcard fieldInfoMap selPermInfo wildcard =

      forM mRelSelPerm $ \relSelPermInfo -> do
        rExtCols <- convWildcard (_tciFieldInfoMap $ _tiCoreInfo relTabInfo) relSelPermInfo wc
-        return $ ECRel relName Nothing $
+        pure $ ECRel relName Nothing $
          SelectG rExtCols Nothing Nothing Nothing Nothing

    relExtCols wc = mapM (mkRelCol wc) relColInfos
@ -99,13 +99,13 @@ resolveStar
 resolveStar fim selPermInfo (SelectG selCols mWh mOb mLt mOf) = do
  procOverrides <- fmap (concat . catMaybes) $ withPathK "columns" $
    indexedForM selCols $ \selCol -> case selCol of
-    (SCStar _) -> return Nothing
+    (SCStar _) -> pure Nothing
    _          -> Just <$> convSelCol fim selPermInfo selCol
  everything <- case wildcards of
-    [] -> return []
+    [] -> pure []
    _  -> convWildcard fim selPermInfo $ maximum wildcards
  let extCols = unionBy equals procOverrides everything
-  return $ SelectG extCols mWh mOb mLt mOf
+  pure $ SelectG extCols mWh mOb mLt mOf
  where
    wildcards = lefts $ map mkEither selCols

@ -121,7 +121,7 @@ convOrderByElem
  => SessVarBldr ('Postgres 'Vanilla) m
  -> (FieldInfoMap (FieldInfo ('Postgres 'Vanilla)), SelPermInfo ('Postgres 'Vanilla))
  -> OrderByCol
-  -> m (AnnOrderByElement ('Postgres 'Vanilla) S.SQLExp)
+  -> m (AnnotatedOrderByElement ('Postgres 'Vanilla) S.SQLExp)
 convOrderByElem sessVarBldr (flds, spi) = \case
  OCPG fldName -> do
    fldInfo <- askFieldInfo flds fldName
@ -134,7 +134,7 @@ convOrderByElem sessVarBldr (flds, spi) = \case
           [ fldName <<> " has type 'geometry'"
           , " and cannot be used in order_by"
           ]
-          else return $ AOCColumn colInfo
+          else pure $ AOCColumn colInfo
      FIRelationship _ -> throw400 UnexpectedPayload $ mconcat
        [ fldName <<> " is a"
        , " relationship and should be expanded"
@ -165,8 +165,7 @@ convOrderByElem sessVarBldr (flds, spi) = \case
          ]
        (relFim, relSelPermInfo) <- fetchRelDet (riName relInfo) (riRTable relInfo)
        resolvedSelFltr <- convAnnBoolExpPartialSQL sessVarBldr $ spiFilter relSelPermInfo
-        AOCObjectRelation relInfo resolvedSelFltr <$>
-          convOrderByElem sessVarBldr (relFim, relSelPermInfo) rest
+        AOCObjectRelation relInfo resolvedSelFltr <$> convOrderByElem sessVarBldr (relFim, relSelPermInfo) rest
      FIRemoteRelationship {} ->
        throw400 UnexpectedPayload (mconcat [ fldName <<> " is a remote field" ])

@ -195,11 +194,11 @@ convSelectQ table fieldInfoMap selPermInfo selQ sessVarBldr prepValBldr = do
      (colInfo, caseBoolExpMaybe) <- convExtSimple fieldInfoMap selPermInfo pgCol
      resolvedCaseBoolExp <-
        traverse (convAnnColumnCaseBoolExpPartialSQL sessVarBldr) caseBoolExpMaybe
-      return (fromCol @('Postgres 'Vanilla) pgCol, mkAnnColumnField colInfo resolvedCaseBoolExp Nothing)
+      pure (fromCol @('Postgres 'Vanilla) pgCol, mkAnnColumnField colInfo resolvedCaseBoolExp Nothing)
    (ECRel relName mAlias relSelQ) -> do
      annRel <- convExtRel fieldInfoMap relName mAlias
                relSelQ sessVarBldr prepValBldr
-      return ( fromRel $ fromMaybe relName mAlias
+      pure ( fromRel $ fromMaybe relName mAlias
             , either AFObjectRelation AFArrayRelation annRel
             )

@ -221,7 +220,7 @@ convSelectQ table fieldInfoMap selPermInfo selQ sessVarBldr prepValBldr = do
      tabArgs = SelectArgs wClause annOrdByM mQueryLimit (fromIntegral <$> mQueryOffset) Nothing

  strfyNum <- stringifyNum . _sccSQLGenCtx <$> askServerConfigCtx
-  return $ AnnSelectG annFlds tabFrom tabPerm tabArgs strfyNum
+  pure $ AnnSelectG annFlds tabFrom tabPerm tabArgs strfyNum

  where
    mQueryOffset = sqOffset selQ
@ -264,10 +263,10 @@ convExtRel fieldInfoMap relName mAlias selQ sessVarBldr prepValBldr = do
  case relTy of
    ObjRel -> do
      when misused $ throw400 UnexpectedPayload objRelMisuseMsg
-      return $ Left $ AnnRelationSelectG (fromMaybe relName mAlias) colMapping $
+      pure $ Left $ AnnRelationSelectG (fromMaybe relName mAlias) colMapping $
        AnnObjectSelectG (_asnFields annSel) relTab $ _tpFilter $ _asnPerm annSel
    ArrRel ->
-      return $ Right $ ASSimple $ AnnRelationSelectG (fromMaybe relName mAlias)
+      pure $ Right $ ASSimple $ AnnRelationSelectG (fromMaybe relName mAlias)
               colMapping annSel
  where
    pgWhenRelErr = "only relationships can be expanded"
--- a/server/src-lib/Hasura/RQL/IR/Select.hs
+++ b/server/src-lib/Hasura/RQL/IR/Select.hs
@ -96,9 +96,9 @@ data ConnectionSplit (b :: BackendType) v
  = ConnectionSplit
  { _csKind    :: !ConnectionSplitKind
  , _csValue   :: !v
-  , _csOrderBy :: !(OrderByItemG b (AnnOrderByElementG b ()))
+  , _csOrderBy :: !(OrderByItemG b (AnnotatedOrderByElement b v))
  } deriving (Functor, Generic, Foldable, Traversable)
-instance (Backend b, Hashable (ColumnInfo b), Hashable v) => Hashable (ConnectionSplit b v)
+instance (Backend b, Hashable (ColumnInfo b), Hashable v, Hashable (BooleanOperators b v)) => Hashable (ConnectionSplit b v)

 data ConnectionSlice
  = SliceFirst !Int
@ -133,7 +133,7 @@ type SelectFrom b = SelectFromG b (SQLExpression b)
 data SelectArgsG (b :: BackendType) v
  = SelectArgs
  { _saWhere    :: !(Maybe (AnnBoolExp b v))
-  , _saOrderBy  :: !(Maybe (NE.NonEmpty (AnnOrderByItemG b v)))
+  , _saOrderBy  :: !(Maybe (NE.NonEmpty (AnnotatedOrderByItemG b v)))
  , _saLimit    :: !(Maybe Int)
  , _saOffset   :: !(Maybe Int64)
  , _saDistinct :: !(Maybe (NE.NonEmpty (Column b)))
@ -159,24 +159,51 @@ noSelectArgs = SelectArgs Nothing Nothing Nothing Nothing Nothing

 -- Order by argument

-data AnnOrderByElementG (b :: BackendType) v
-  = AOCColumn !(ColumnInfo b)
-  | AOCObjectRelation !(RelInfo b) !v !(AnnOrderByElementG b v)
-  | AOCArrayAggregation !(RelInfo b) !v !(AnnAggregateOrderBy b)
+-- | The order by element for a computed field based on its return type
+data ComputedFieldOrderByElement (b :: BackendType) v
+  = CFOBEScalar !(ScalarType b)
+  -- ^ Sort by the scalar computed field
+  | CFOBETableAggregation !(TableName b)
+    !(AnnBoolExp b v) -- ^ Permission filter of the retuning table
+    !(AnnotatedAggregateOrderBy b)
+  -- ^ Sort by aggregation fields of table rows returned by computed field
  deriving (Generic, Functor, Foldable, Traversable)
-deriving instance (Backend b, Eq v) => Eq (AnnOrderByElementG b v)
-instance (Backend b, Hashable v) => Hashable (AnnOrderByElementG b v)
+deriving instance (Backend b, Eq v, Eq (BooleanOperators b v)) => Eq (ComputedFieldOrderByElement b v)
+instance (Backend b, Hashable v, Hashable (BooleanOperators b v)) => Hashable (ComputedFieldOrderByElement b v)

-data AnnAggregateOrderBy (b :: BackendType)
+data ComputedFieldOrderBy (b :: BackendType) v
+  = ComputedFieldOrderBy
+  { _cfobXField          :: !(XComputedField b)
+  , _cfobName            :: !ComputedFieldName
+  , _cfobFunction        :: !(FunctionName b)
+  , _cfobFunctionArgsExp :: !(FunctionArgsExpTableRow b v)
+  , _cfobOrderByElement  :: !(ComputedFieldOrderByElement b v)
+  } deriving (Generic, Functor, Foldable, Traversable)
+deriving instance (Backend b, Eq v, Eq (BooleanOperators b v)) => Eq (ComputedFieldOrderBy b v)
+instance (Backend b, Hashable v, Hashable (BooleanOperators b v)) => Hashable (ComputedFieldOrderBy b v)
+
+data AnnotatedOrderByElement (b :: BackendType) v
+  = AOCColumn !(ColumnInfo b)
+  | AOCObjectRelation !(RelInfo b)
+    !(AnnBoolExp b v) -- ^ Permission filter of the remote table to which the relationship is defined
+    !(AnnotatedOrderByElement b v)
+  | AOCArrayAggregation !(RelInfo b)
+    !(AnnBoolExp b v) -- ^ Permission filter of the remote table to which the relationship is defined
+    !(AnnotatedAggregateOrderBy b)
+  | AOCComputedField !(ComputedFieldOrderBy b v)
+  deriving (Generic, Functor, Foldable, Traversable)
+deriving instance (Backend b, Eq v, Eq (BooleanOperators b v)) => Eq (AnnotatedOrderByElement b v)
+instance (Backend b, Hashable v, Hashable (BooleanOperators b v)) => Hashable (AnnotatedOrderByElement b v)
+
+data AnnotatedAggregateOrderBy (b :: BackendType)
  = AAOCount
  | AAOOp !Text !(ColumnInfo b)
  deriving (Generic)
-deriving instance (Backend b) => Eq (AnnAggregateOrderBy b)
-instance (Backend b) => Hashable (AnnAggregateOrderBy b)
+deriving instance (Backend b) => Eq (AnnotatedAggregateOrderBy b)
+instance (Backend b) => Hashable (AnnotatedAggregateOrderBy b)

-type AnnOrderByElement b v = AnnOrderByElementG b (AnnBoolExp b v)
-type AnnOrderByItemG b v = OrderByItemG b (AnnOrderByElement b v)
-type AnnOrderByItem b = AnnOrderByItemG b (SQLExpression b)
+type AnnotatedOrderByItemG b v = OrderByItemG b (AnnotatedOrderByElement b v)
+type AnnotatedOrderByItem b = AnnotatedOrderByItemG b (SQLExpression b)


 -- Fields
@ -466,6 +493,17 @@ type FunctionArgExp          b   = FunctionArgsExpG (SQLExpression b)
 emptyFunctionArgsExp :: FunctionArgsExpG a
 emptyFunctionArgsExp = FunctionArgsExp [] HM.empty

+functionArgsWithTableRowAndSession
+  :: v
+  -> FunctionTableArgument
+  -> Maybe FunctionSessionArgument
+  -> [ArgumentExp b v]
+functionArgsWithTableRowAndSession  _    _              Nothing = [AETableRow Nothing] -- No session argument
+functionArgsWithTableRowAndSession  sess (FTAFirst)     _       = [AETableRow Nothing, AESession sess]
+functionArgsWithTableRowAndSession  sess (FTANamed _ 0) _       = [AETableRow Nothing, AESession sess] -- Index is 0 implies table argument is first
+functionArgsWithTableRowAndSession  sess _              _       = [AESession sess, AETableRow Nothing]
+
+
 -- | If argument positional index is less than or equal to length of
 -- 'positional' arguments then insert the value in 'positional' arguments else
 -- insert the value with argument name in 'named' arguments
@ -488,4 +526,4 @@ insertFunctionArg argName idx value (FunctionArgsExp positional named) =

 $(makeLenses ''AnnSelectG)
 $(makePrisms ''AnnFieldG)
-$(makePrisms ''AnnOrderByElementG)
+$(makePrisms ''AnnotatedOrderByElement)
--- a/server/tests-py/queries/graphql_query/order_by/Track_order_by_size.yaml
+++ b/server/tests-py/queries/graphql_query/order_by/Track_order_by_size.yaml
@ -0,0 +1,21 @@
+description: Fetch tracks order by their size which is a computed field
+url: /v1/graphql
+status: 200
+query:
+  query: |
+    query {
+      Track(order_by: {size: desc}, limit: 2){
+        name
+        bytes
+        size
+      }
+    }
+response:
+  data:
+    Track:
+    - name: Restless
+      bytes: 9836284
+      size: 9
+    - name: Mistress
+      bytes: 7521946
+      size: 7
--- a/server/tests-py/queries/graphql_query/order_by/author_order_by_get_articles_aggregate.yaml
+++ b/server/tests-py/queries/graphql_query/order_by/author_order_by_get_articles_aggregate.yaml
@ -0,0 +1,31 @@
+description: Fetch author with order by using computed field aggregate returns set of articles with a search query via session variable
+url: /v1/graphql
+status: 200
+headers:
+  X-Hasura-Role: admin
+  X-Hasura-Search: '1'
+query:
+  query: |
+    query{
+      author(order_by: {get_articles_aggregate: {count: desc}}){
+        id
+        name
+        get_articles{
+          id
+          title
+          content
+        }
+      }
+    }
+response:
+  data:
+    author:
+    - id: 1
+      name: Author 1
+      get_articles:
+      - id: 1
+        title: Article 1
+        content: Sample article content 1
+    - id: 2
+      name: Author 2
+      get_articles: []
--- a/server/tests-py/queries/graphql_query/order_by/setup.yaml
+++ b/server/tests-py/queries/graphql_query/order_by/setup.yaml
@ -11,11 +11,13 @@ args:
        phone INTEGER,
        address TEXT
      );
+
      create table author(
          id serial primary key,
          name text unique,
          contact_id INTEGER REFERENCES contact(id)
      );
+
      CREATE TABLE article (
        id SERIAL PRIMARY KEY,
        title TEXT,
@ -24,14 +26,27 @@ args:
        is_published BOOLEAN,
        published_on TIMESTAMP
      );
+
+      CREATE FUNCTION get_articles(hasura_session json, author_row author)
+      RETURNS SETOF article AS $$
+        SELECT *
+        FROM article
+        WHERE author_id = author_row.id AND
+          ( title ilike  ('%' || (hasura_session ->> 'x-hasura-search') || '%')
+            OR content  ilike  ('%' || (hasura_session ->> 'x-hasura-search') || '%')
+          )
+      $$ LANGUAGE SQL STABLE;
+
      insert into contact (phone)
      values
      (1234567890),
      (1234567891);
+
      insert into author (name, contact_id)
      values
      ('Author 1', 2),
      ('Author 2', 1);
+
      insert into article (title,content,author_id,is_published)
      values
      (
@ -56,6 +71,7 @@ args:
        album_id INTEGER NOT NULL PRIMARY KEY,
        title TEXT NOT NULL
      );
+
      create table "Track" (
      track_id INTEGER NOT NULL PRIMARY KEY,
      name TEXT NOT NULL,
@ -63,8 +79,10 @@ args:
      milliseconds INTEGER NOT NULL,
      bytes INTEGER NOT NULL
      );
+
      insert into "Album" (album_id, title)
      values ( 1, 'Big Ones' ), (2, 'Face Lift');
+
      insert into "Track"
      (track_id, name, album_id, milliseconds, bytes)
      values
@ -75,16 +93,24 @@ args:
      ( 5, 'Random', 2, 1094732, 6032547) ,
      ( 6, 'Good One', 2, 346208, 6732987) ,
      ( 7, 'Mistress', 2, 420985, 7521946);
+
+      CREATE FUNCTION track_size_mb(track_row "Track")
+      RETURNS INTEGER AS $$
+        SELECT (track_row.bytes / 1048576)
+      $$ LANGUAGE SQL STABLE;
+
      CREATE table "Tag" (
        id SERIAL PRIMARY KEY,
        name TEXT NOT NULL,
        album_id INTEGER NOT NULL REFERENCES "Album"(album_id)
      );
+
      INSERT INTO "Tag" (name, album_id)
      VALUES
      ( 'Rock',    1),
      ( 'Folk',    1),
      ( 'Hip Hop', 2);
+
      CREATE TABLE employee (
        id SERIAL PRIMARY KEY,
        name TEXT NOT NULL UNIQUE,
@ -109,6 +135,16 @@ args:
    schema: public
    name: article

+# Computed field to author table
+- type: add_computed_field
+  args:
+    table: author
+    name: get_articles
+    definition:
+      function: get_articles
+      table_argument: author_row
+      session_argument: hasura_session
+
 #Object relationship
 - type: create_object_relationship
  args:
@ -161,6 +197,14 @@ args:
        table: Track
        column: album_id

+# Create computed field for Track table
+- type: add_computed_field
+  args:
+    table: Track
+    name: size
+    definition:
+      function: track_size_mb
+
 # Insert values in Album and Track
 - type: track_table
  args:
--- a/server/tests-py/queries/graphql_query/order_by/teardown.yaml
+++ b/server/tests-py/queries/graphql_query/order_by/teardown.yaml
@ -3,9 +3,11 @@ args:
 - type: run_sql
  args:
    sql: |
+      DROP FUNCTION get_articles(json, author);
      DROP TABLE article;
      DROP TABLE author;
      DROP TABLE contact;
+      DROP FUNCTION track_size_mb("Track");
      DROP TABLE "Track";
      DROP TABLE "Tag";
      DROP TABLE "Album";
--- a/server/tests-py/test_graphql_queries.py
+++ b/server/tests-py/test_graphql_queries.py
@ -894,6 +894,12 @@ class TestGraphQLQueryOrderBy:
    def test_album_order_by_tracks_tags(self, hge_ctx, transport):
        check_query_f(hge_ctx, self.dir() + '/album_order_by_tracks_tags.yaml', transport)

+    def test_Track_order_by_size(self, hge_ctx, transport):
+        check_query_f(hge_ctx, self.dir() + '/Track_order_by_size.yaml', transport)
+
+    def test_author_order_by_get_articles_aggregate(self, hge_ctx, transport):
+        check_query_f(hge_ctx, self.dir() + '/author_order_by_get_articles_aggregate.yaml', transport)
+
    @classmethod
    def dir(cls):
        return 'queries/graphql_query/order_by'