mirror of
https://github.com/neilotoole/sq.git
synced 2024-12-18 21:52:28 +03:00
252 lines
6.3 KiB
Go
252 lines
6.3 KiB
Go
package mysql
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import (
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"bytes"
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"fmt"
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"strings"
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"github.com/neilotoole/sq/libsq/ast"
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"github.com/neilotoole/sq/libsq/ast/render"
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"github.com/neilotoole/sq/libsq/core/errz"
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"github.com/neilotoole/sq/libsq/core/kind"
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"github.com/neilotoole/sq/libsq/core/schema"
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"github.com/neilotoole/sq/libsq/core/stringz"
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)
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func dbTypeNameFromKind(knd kind.Kind) string {
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switch knd { //nolint:exhaustive // ignore kind.Unknown and kind.Null
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case kind.Text:
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return "TEXT"
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case kind.Int:
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return "INT"
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case kind.Float:
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return "DOUBLE"
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case kind.Decimal:
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return "DECIMAL"
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case kind.Bool:
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return "TINYINT(1)"
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case kind.Datetime:
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return "DATETIME"
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case kind.Time:
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return "TIME"
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case kind.Date:
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return "DATE"
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case kind.Bytes:
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return "BLOB"
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default:
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panic(fmt.Sprintf("unsupported data kind {%s}", knd))
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}
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}
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// createTblKindDefaults is a map of Kind to the value
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// to use for a column's DEFAULT clause in a CREATE TABLE statement.
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//
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// Note that MySQL (at least of v5.6) doesn't support DEFAULT values
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// for TEXT or BLOB columns.
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// https://bugs.mysql.com/bug.php?id=21532
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var createTblKindDefaults = map[kind.Kind]string{ //nolint:exhaustive
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kind.Text: ``,
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kind.Int: `DEFAULT 0`,
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kind.Float: `DEFAULT 0`,
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kind.Decimal: `DEFAULT 0`,
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kind.Bool: `DEFAULT 0`,
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kind.Datetime: `DEFAULT '1970-01-01 00:00:00'`,
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kind.Date: `DEFAULT '1970-01-01'`,
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kind.Time: `DEFAULT '00:00:00'`,
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kind.Bytes: ``,
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kind.Unknown: ``,
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}
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//nolint:funlen
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func buildCreateTableStmt(tblDef *schema.Table) string {
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buf := &bytes.Buffer{}
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cols := make([]string, len(tblDef.Cols))
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for i, col := range tblDef.Cols {
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buf.WriteRune('`')
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buf.WriteString(col.Name)
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buf.WriteString("` ")
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buf.WriteString(dbTypeNameFromKind(col.Kind))
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if col.HasDefault {
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buf.WriteRune(' ')
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buf.WriteString(createTblKindDefaults[col.Kind])
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}
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if col.NotNull {
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buf.WriteString(" NOT NULL")
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}
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if col.Name == tblDef.PKColName && tblDef.AutoIncrement {
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buf.WriteString(" AUTO_INCREMENT")
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}
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cols[i] = buf.String()
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buf.Reset()
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}
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pk := ""
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if tblDef.PKColName != "" {
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buf.WriteString("PRIMARY KEY (`")
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buf.WriteString(tblDef.PKColName)
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buf.WriteString("`),\n")
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buf.WriteString("UNIQUE KEY `")
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buf.WriteString(tblDef.Name)
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buf.WriteRune('_')
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buf.WriteString(tblDef.PKColName)
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buf.WriteString("_uindex` (`")
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buf.WriteString(tblDef.PKColName)
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buf.WriteString("`)")
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pk = buf.String()
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}
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var uniq string
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buf.Reset()
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for _, col := range tblDef.Cols {
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if col.Name == tblDef.PKColName {
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// if the table has a PK, then we've already added a unique constraint for it above
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continue
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}
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if col.Unique {
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if buf.Len() > 0 {
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buf.WriteString(",\n")
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}
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buf.WriteString("UNIQUE KEY `")
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buf.WriteString(tblDef.Name)
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buf.WriteRune('_')
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buf.WriteString(col.Name)
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buf.WriteString("_uindex` (`")
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buf.WriteString(col.Name)
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buf.WriteString("`)")
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}
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}
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uniq = buf.String()
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var fk string
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buf.Reset()
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for _, col := range tblDef.Cols {
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if col.ForeignKey == nil {
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continue
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}
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if buf.Len() > 0 {
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buf.WriteString(",\n")
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}
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buf.WriteString("KEY `")
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buf.WriteString(tblDef.Name)
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buf.WriteRune('_')
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buf.WriteString(col.Name)
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buf.WriteRune('_')
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buf.WriteString(col.ForeignKey.RefTable)
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buf.WriteRune('_')
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buf.WriteString(col.ForeignKey.RefCol)
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buf.WriteString("_key` (`")
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buf.WriteString(col.Name)
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buf.WriteString("`),\nCONSTRAINT `")
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buf.WriteString(tblDef.Name)
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buf.WriteRune('_')
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buf.WriteString(col.Name)
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buf.WriteRune('_')
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buf.WriteString(col.ForeignKey.RefTable)
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buf.WriteRune('_')
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buf.WriteString(col.ForeignKey.RefCol)
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buf.WriteString("_fk` FOREIGN KEY (`")
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buf.WriteString(col.Name)
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buf.WriteString("`) REFERENCES `")
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buf.WriteString(col.ForeignKey.RefTable)
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buf.WriteString("` (`")
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buf.WriteString(col.ForeignKey.RefCol)
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buf.WriteString("`) ON DELETE ")
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if col.ForeignKey.OnDelete == "" {
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buf.WriteString("CASCADE")
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} else {
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buf.WriteString(col.ForeignKey.OnDelete)
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}
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buf.WriteString(" ON UPDATE ")
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if col.ForeignKey.OnUpdate == "" {
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buf.WriteString("CASCADE")
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} else {
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buf.WriteString(col.ForeignKey.OnUpdate)
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}
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}
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fk = buf.String()
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buf.Reset()
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buf.WriteString("CREATE TABLE `")
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buf.WriteString(tblDef.Name)
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buf.WriteString("` (\n")
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for x := 0; x < len(cols)-1; x++ {
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buf.WriteString(cols[x])
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buf.WriteString(",\n")
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}
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buf.WriteString(cols[len(cols)-1])
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if pk != "" {
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buf.WriteString(",\n")
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buf.WriteString(pk)
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}
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if uniq != "" {
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buf.WriteString(",\n")
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buf.WriteString(uniq)
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}
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if fk != "" {
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buf.WriteString(",\n")
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buf.WriteString(fk)
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}
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buf.WriteString("\n)")
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return buf.String()
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}
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func buildUpdateStmt(tbl string, cols []string, where string) (string, error) {
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if len(cols) == 0 {
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return "", errz.Errorf("no columns provided")
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}
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buf := strings.Builder{}
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buf.WriteString("UPDATE `")
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buf.WriteString(tbl)
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buf.WriteString("` SET `")
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buf.WriteString(strings.Join(cols, "` = ?, `"))
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buf.WriteString("` = ?")
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if where != "" {
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buf.WriteString(" WHERE ")
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buf.WriteString(where)
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}
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return buf.String(), nil
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}
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// renderFuncRowNum renders the rownum() function.
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//
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// MySQL didn't introduce ROW_NUMBER() until 8.0, and we're still
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// trying to support 5.6 and 5.7. So, we're using a hack, as
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// described here: https://www.mysqltutorial.org/mysql-row_number/
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//
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// SET @row_number = 0;
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// SELECT
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// (@row_number:=@row_number + 1) AS num,
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// actor_id,
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// first_name,
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// last_name
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// FROM actor
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// ORDER BY first_name
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//
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// The function puts the SET statement into the PreExecStmts fragment,
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// which then gets executed before the main body of the query.
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//
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// For MySQL 8+, we could use the ROW_NUMBER() function, but right now
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// the code isn't really set up to execute different impls for different
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// driver versions. Although, this is probably something we need to face up to.
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func renderFuncRowNum(rc *render.Context, _ *ast.FuncNode) (string, error) { //nolint:unparam
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// We use a unique variable name to avoid collisions if there are
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// multiple uses of rownum() in the same query.
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variable := "@row_number_" + stringz.Uniq8()
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rc.Fragments.PreExecStmts = append(rc.Fragments.PreExecStmts, "SET "+variable+" = 0;")
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rc.Fragments.PostExecStmts = append(rc.Fragments.PostExecStmts, "SET "+variable+" = NULL;")
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// e.g. (@row_number_abcd1234:=@row_number_abcd1234 + 1)
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return "(" + variable + ":=" + variable + " + 1)", nil
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}
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