Method parseCommonTableExpr

pkg/sql/parser/cte.go:113–222

parseCommonTableExpr parses a single Common Table Expression. It handles CTE name, optional column list, AS keyword, and the CTE query in parentheses. Syntax: cte_name [(column_list)] AS (query)

()

//
// Syntax: cte_name [(column_list)] AS (query)
func (p *Parser) parseCommonTableExpr() (*ast.CommonTableExpr, error) {
	// Check recursion depth to prevent stack overflow in recursive CTEs
	// This is critical since CTEs can call parseStatement which leads back to more CTEs
	p.depth++
	defer func() { p.depth-- }()

	if p.depth > MaxRecursionDepth {
		return nil, goerrors.InvalidCTEError(
			fmt.Sprintf("maximum recursion depth exceeded (%d) - CTE too deeply nested", MaxRecursionDepth),
			p.currentLocation(),
			"",
		)
	}

	// Parse CTE name (supports double-quoted identifiers)
	if !p.isIdentifier() {
		return nil, p.expectedError("CTE name")
	}
	cteNamePos := p.currentLocation()
	name := p.currentToken.Token.Value
	p.advance()

	// Parse optional column list
	var columns []string
	if p.isType(models.TokenTypeLParen) {
		p.advance() // Consume (

		for {
			if !p.isIdentifier() {
				return nil, p.expectedError("column name")
			}
			columns = append(columns, p.currentToken.Token.Value)
			p.advance()

			if p.isType(models.TokenTypeComma) {
				p.advance() // Consume comma
				continue
			}
			break
		}

		if !p.isType(models.TokenTypeRParen) {
			return nil, p.expectedError(")")
		}
		p.advance() // Consume )
	}

	// Parse AS keyword
	if !p.isType(models.TokenTypeAs) {
		return nil, p.expectedError("AS")
	}
	p.advance()

	// Parse optional MATERIALIZED / NOT MATERIALIZED
	// Syntax: AS [NOT] MATERIALIZED (query)
	var materialized *bool
	if p.isType(models.TokenTypeNot) {
		p.advance() // Consume NOT