Method parseWindowFrameClause

parser/parser_query.go:655–697

(pos Pos)

}

func (p *Parser) parseWindowFrameClause(pos Pos) (*WindowFrameClause, error) {
	var windowFrameType string
	if p.matchKeyword(KeywordRows) || p.matchKeyword(KeywordRange) {
		windowFrameType = p.last().String
		_ = p.lexer.consumeToken()
	} else {
		return nil, fmt.Errorf("expected ROWS or RANGE for window frame")
	}

	var expr Expr
	if p.tryConsumeKeywords(KeywordBetween) {
		left, err := p.parseFrameExtent()
		if err != nil {
			return nil, err
		}
		andPos := p.Pos()
		if err := p.expectKeyword(KeywordAnd); err != nil {
			return nil, err
		}
		right, err := p.parseFrameExtent()
		if err != nil {
			return nil, err
		}
		expr = &BetweenClause{
			Between: left,
			AndPos:  andPos,
			And:     right,
		}
	} else {
		// single extent
		extent, err := p.parseFrameExtent()
		if err != nil {
			return nil, err
		}
		expr = extent
	}

	return &WindowFrameClause{
		FramePos: pos,
		Type:     windowFrameType,
		Extend:   expr,
	}, nil
}

// parseFrameExtent parses a single frame extent
func (p *Parser) parseFrameExtent() (Expr, error) {