Method parseFunctionCall

pkg/sql/parser/window.go:30–355

SUM(salary) OVER (PARTITION BY dept ORDER BY date ROWS UNBOUNDED PRECEDING) -> window function with frame

(funcName string)

// SUM(salary) OVER (PARTITION BY dept ORDER BY date ROWS UNBOUNDED PRECEDING) -> window function with frame
func (p *Parser) parseFunctionCall(funcName string) (*ast.FunctionCall, error) {
	// Expect opening parenthesis
	if !p.isType(models.TokenTypeLParen) {
		return nil, p.expectedError("(")
	}
	p.advance() // Consume (

	// Parse function arguments
	var arguments []ast.Expression
	var distinct bool

	// Check for DISTINCT keyword
	if p.isType(models.TokenTypeDistinct) {
		distinct = true
		p.advance()
	}

	// Parse arguments if not empty
	if !p.isType(models.TokenTypeRParen) {
		for !p.isType(models.TokenTypeOrder) {
			// Named argument form: `name => expr` (Snowflake FLATTEN,
			// BigQuery, Oracle, PostgreSQL procedural calls). Detect by a
			// bare identifier immediately followed by =>.
			if p.isIdentifier() &&
				p.peekToken().Token.Type == models.TokenTypeRArrow {
				namePos := p.currentLocation()
				argName := p.currentToken.Token.Value
				p.advance() // name
				p.advance() // =>
				value, err := p.parseExpression()
				if err != nil {
					return nil, err
				}
				arguments = append(arguments, &ast.NamedArgument{
					Name:  argName,
					Value: value,
					Pos:   namePos,
				})
				if p.isType(models.TokenTypeComma) {
					p.advance()
					continue
				}
				if p.isType(models.TokenTypeRParen) {
					break
				}
				return nil, p.expectedError(", or )")
			}

			arg, err := p.parseExpression()
			if err != nil {
				return nil, err
			}
			arguments = append(arguments, arg)

			// Check for comma or end of arguments
			if p.isType(models.TokenTypeComma) {
				p.advance() // Consume comma
			} else if p.isType(models.TokenTypeRParen) || p.isType(models.TokenTypeOrder) {