Method parseOneTimeTravelClause

pkg/sql/parser/pivot.go:302–357

()

}

func (p *Parser) parseOneTimeTravelClause() (*ast.TimeTravelClause, error) {
	pos := p.currentLocation()
	kind := strings.ToUpper(p.currentToken.Token.Value)
	p.advance() // Consume AT / BEFORE / CHANGES
	if !p.isType(models.TokenTypeLParen) {
		return nil, p.expectedError("( after " + kind)
	}
	p.advance() // Consume (

	clause := &ast.TimeTravelClause{
		Kind:  kind,
		Named: map[string]ast.Expression{},
		Pos:   pos,
	}

	// Parse comma-separated named arguments: name => expr [, name => expr]...
	// Snowflake uses TIMESTAMP, OFFSET, STATEMENT, INFORMATION as argument
	// names; these tokenize as dedicated keyword types, not identifiers.
	// Accept any non-punctuation token with a non-empty value as the name.
	for {
		argName := strings.ToUpper(p.currentToken.Token.Value)
		if argName == "" || p.isType(models.TokenTypeRParen) ||
			p.isType(models.TokenTypeComma) || p.isType(models.TokenTypeLParen) {
			return nil, p.expectedError("argument name in " + kind)
		}
		p.advance()
		if p.currentToken.Token.Type != models.TokenTypeRArrow {
			return nil, p.expectedError("=> after " + argName)
		}
		p.advance() // =>
		// Values are typically literal expressions, but may also be bare
		// keywords like DEFAULT or APPEND_ONLY for CHANGES (INFORMATION => …).
		var value ast.Expression
		if v, err := p.parseExpression(); err == nil {
			value = v
		} else if p.currentToken.Token.Value != "" &&
			!p.isType(models.TokenTypeRParen) && !p.isType(models.TokenTypeComma) {
			value = &ast.Identifier{Name: p.currentToken.Token.Value}
			p.advance()
		} else {
			return nil, err
		}
		clause.Named[argName] = value
		if p.isType(models.TokenTypeComma) {
			p.advance()
			continue
		}
		break
	}

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

// isSnowflakeTimeTravelStart returns true when the current token begins an