Method getCTEColumnNames

internal/x/expander/expander.go:159–205

getCTEColumnNames gets the column names for a CTE by constructing a query with proper context

(ctx context.Context, stmt *ast.SelectStmt, targetCTE *ast.CommonTableExpr)

// getCTEColumnNames gets the column names for a CTE by constructing a query with proper context
func (e *Expander) getCTEColumnNames(ctx context.Context, stmt *ast.SelectStmt, targetCTE *ast.CommonTableExpr) ([]string, error) {
	// Build a temporary query: WITH <all CTEs up to and including target> SELECT * FROM <targetCTE>
	var ctesToInclude []ast.Node
	for _, cteNode := range stmt.WithClause.Ctes.Items {
		ctesToInclude = append(ctesToInclude, cteNode)
		cte, ok := cteNode.(*ast.CommonTableExpr)
		if ok && cte.Ctename != nil && targetCTE.Ctename != nil && *cte.Ctename == *targetCTE.Ctename {
			break
		}
	}

	// Create a SELECT * FROM <ctename> with the relevant CTEs
	cteName := ""
	if targetCTE.Ctename != nil {
		cteName = *targetCTE.Ctename
	}

	tempStmt := &ast.SelectStmt{
		WithClause: &ast.WithClause{
			Ctes:      &ast.List{Items: ctesToInclude},
			Recursive: stmt.WithClause.Recursive,
		},
		TargetList: &ast.List{
			Items: []ast.Node{
				&ast.ResTarget{
					Val: &ast.ColumnRef{
						Fields: &ast.List{
							Items: []ast.Node{&ast.A_Star{}},
						},
					},
				},
			},
		},
		FromClause: &ast.List{
			Items: []ast.Node{
				&ast.RangeVar{
					Relname: &cteName,
				},
			},
		},
	}

	tempRaw := &ast.RawStmt{Stmt: tempStmt}
	tempQuery := ast.Format(tempRaw, e.dialect)

	return e.getColumnNames(ctx, tempQuery)
}

// expandInsertStmt expands * in an INSERT statement's RETURNING clause
func (e *Expander) expandInsertStmt(ctx context.Context, stmt *ast.InsertStmt) error {