mirror of
https://github.com/neilotoole/sq.git
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103 lines
2.6 KiB
Go
103 lines
2.6 KiB
Go
package render
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import (
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"github.com/samber/lo"
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"github.com/neilotoole/sq/libsq/ast"
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"github.com/neilotoole/sq/libsq/core/errz"
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"github.com/neilotoole/sq/libsq/core/jointype"
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)
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func renderJoinType(jt jointype.Type) (string, error) {
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switch jt {
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case jointype.Inner:
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return "INNER JOIN", nil
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case jointype.Left:
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return "LEFT JOIN", nil
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case jointype.LeftOuter:
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return "LEFT OUTER JOIN", nil
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case jointype.Right:
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return "RIGHT JOIN", nil
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case jointype.RightOuter:
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return "RIGHT OUTER JOIN", nil
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case jointype.FullOuter:
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return "FULL OUTER JOIN", nil
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case jointype.Cross:
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return "CROSS JOIN", nil
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default:
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return "", errz.Errorf("unknown join type: %s", jt)
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}
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}
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func doJoin(rc *Context, leftTbl *ast.TblSelectorNode, joins []*ast.JoinNode) (string, error) {
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enquote := rc.Dialect.Enquote
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allTbls := make([]*ast.TblSelectorNode, len(joins)+1)
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allTbls[0] = leftTbl
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for i := range joins {
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allTbls[i+1] = joins[i].Table()
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}
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sql := "FROM "
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sql = sqlAppend(sql, leftTbl.Table().Render(enquote))
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if leftTbl.Alias() != "" {
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sql = sqlAppend(sql, "AS "+enquote(leftTbl.Alias()))
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}
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for i, join := range joins {
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var s string
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var err error
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jt := join.JoinType()
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if !lo.Contains(rc.Dialect.Joins, jt) {
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return "", errz.Errorf("driver {%s} does not support join type {%s}",
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rc.Dialect.Type, jt)
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}
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if s, err = renderJoinType(jt); err != nil {
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return "", err
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}
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tbl := join.Table()
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s = sqlAppend(s, tbl.Table().Render(enquote))
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if tbl.Alias() != "" {
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s = sqlAppend(s, "AS "+enquote(tbl.Alias()))
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}
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if expr := join.Predicate(); expr != nil {
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if !join.JoinType().HasPredicate() {
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return "", errz.Errorf("invalid join: {%s} does not accept a predicate: %s",
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join.JoinType(), join.Text())
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}
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s = sqlAppend(s, "ON")
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// Special handling for: .left_tbl | join(.right_tbl, .col)
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// This is rendered as:
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// FROM left_tbl JOIN right_tbl ON left_tbl.col = right_tbl.col
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children := expr.Children()
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if len(children) == 1 {
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if colSel, ok := children[0].(*ast.ColSelectorNode); ok {
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// TODO: should be able to handle ast.TblColSelector also?
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colName := colSel.ColName()
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text := allTbls[i].TblAliasOrName().Render(enquote) + "." + enquote(colName)
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text += " = "
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text += allTbls[i+1].TblAliasOrName().Render(enquote) + "." + enquote(colName)
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s = sqlAppend(s, text)
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sql = sqlAppend(sql, s)
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continue
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}
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}
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var text string
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if text, err = rc.Renderer.Expr(rc, expr); err != nil {
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return "", err
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}
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s = sqlAppend(s, text)
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}
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sql = sqlAppend(sql, s)
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}
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return sql, nil
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}
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