Add support for window names in WindowExpr (#259)

Author: chinhnguyenh

parser/ast.go

@@ -4810,6 +4810,7 @@ func (l *LimitByClause) Accept(visitor ASTVisitor) error {
 type WindowExpr struct {
 	LeftParenPos  Pos
 	RightParenPos Pos
+	WindowName    *Ident
 	PartitionBy   *PartitionByClause
 	OrderBy       *OrderByClause
 	Frame         *WindowFrameClause
@@ -4826,6 +4827,11 @@ func (w *WindowExpr) End() Pos {
 func (w *WindowExpr) Accept(visitor ASTVisitor) error {
 	visitor.Enter(w)
 	defer visitor.Leave(w)
+	if w.WindowName != nil {
+		if err := w.WindowName.Accept(visitor); err != nil {
+			return err
+		}
+	}
 	if w.PartitionBy != nil {
 		if err := w.PartitionBy.Accept(visitor); err != nil {
 			return err

parser/format.go

@@ -2755,7 +2755,14 @@ func (w *WindowClause) FormatSQL(formatter *Formatter) {
 func (w *WindowExpr) FormatSQL(formatter *Formatter) {
 	formatter.WriteByte('(')
 	hasPart := false
+	if w.WindowName != nil {
+		formatter.WriteExpr(w.WindowName)
+		hasPart = true
+	}
 	if w.PartitionBy != nil {
+		if hasPart {
+			formatter.WriteByte(whitespace)
+		}
 		formatter.WriteExpr(w.PartitionBy)
 		hasPart = true
 	}

parser/parser_query.go

@@ -824,6 +824,14 @@ func (p *Parser) parseWindowCondition(pos Pos) (*WindowExpr, error) {
 	if err := p.expectTokenKind(TokenKindLParen); err != nil {
 		return nil, err
 	}
+	var windowName *Ident
+	if p.canParseWindowNameInParens() {
+		var err error
+		windowName, err = p.parseIdent()
+		if err != nil {
+			return nil, err
+		}
+	}
 	partitionBy, err := p.tryParsePartitionByClause(pos)
 	if err != nil {
 		return nil, err
@@ -843,12 +851,41 @@ func (p *Parser) parseWindowCondition(pos Pos) (*WindowExpr, error) {
 	return &WindowExpr{
 		LeftParenPos:  pos,
 		RightParenPos: rightParenPos,
+		WindowName:    windowName,
 		PartitionBy:   partitionBy,
 		OrderBy:       orderBy,
 		Frame:         frame,
 	}, nil
 }
 
+func (p *Parser) canParseWindowNameInParens() bool {
+	if !p.matchTokenKind(TokenKindIdent) {
+		return false
+	}
+	if !p.matchTokenKind(TokenKindKeyword) {
+		return true
+	}
+
+	savedState := p.lexer.saveState()
+	defer p.lexer.restoreState(savedState)
+
+	switch {
+	case p.matchKeyword(KeywordPartition), p.matchKeyword(KeywordOrder):
+		_ = p.lexer.consumeToken()
+		return !p.matchKeyword(KeywordBy)
+	case p.matchKeyword(KeywordRows), p.matchKeyword(KeywordRange):
+		_ = p.lexer.consumeToken()
+		return !p.matchKeyword(KeywordBetween) &&
+			!p.matchKeyword(KeywordCurrent) &&
+			!p.matchKeyword(KeywordUnbounded) &&
+			!p.matchTokenKind(TokenKindInt) &&
+			!p.matchTokenKind(TokenKindLBrace) &&
+			!p.matchKeyword(KeywordInterval)
+	default:
+		return true
+	}
+}
+
 func (p *Parser) parseWindowClause(pos Pos) (*WindowClause, error) {
 	if err := p.expectKeyword(KeywordWindow); err != nil {
 		return nil, err

parser/testdata/ddl/output/create_materialized_view_with_empty_table_schema.sql.golden.json

@@ -307,6 +307,7 @@
                           "OverExpr": {
                             "LeftParenPos": 306,
                             "RightParenPos": 347,
+                            "WindowName": null,
                             "PartitionBy": {
                               "PartitionPos": 306,
                               "Expr": {

parser/testdata/query/format/beautify/select_window_keyword_name_in_parens.sql

@@ -0,0 +1,13 @@
+-- Origin SQL:
+SELECT sum(x) OVER (order) AS sum_over_order
+FROM t
+WINDOW order AS (PARTITION BY team ORDER BY ts);
+
+
+-- Beautify SQL:
+SELECT
+  sum(x) OVER (order) AS sum_over_order
+FROM
+  t
+WINDOW order AS (PARTITION BY team ORDER BY
+  ts);

parser/testdata/query/format/beautify/select_window_named_in_parens.sql

@@ -0,0 +1,13 @@
+-- Origin SQL:
+SELECT sum(x) OVER (w) AS sum_over_w
+FROM t
+WINDOW w AS (PARTITION BY y ORDER BY x);
+
+
+-- Beautify SQL:
+SELECT
+  sum(x) OVER (w) AS sum_over_w
+FROM
+  t
+WINDOW w AS (PARTITION BY y ORDER BY
+  x);

parser/testdata/query/format/beautify/select_window_named_reference_extensions.sql

@@ -0,0 +1,17 @@
+-- Origin SQL:
+SELECT sum(x) OVER (w1 ORDER BY ts ROWS BETWEEN 1 PRECEDING AND CURRENT ROW) AS rolling_sum,
+       avg(x) OVER (w2)                                                      AS avg_over_w2
+FROM t
+WINDOW w1 AS (PARTITION BY team),
+       w2 AS (w1 ORDER BY ts ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW);
+
+
+-- Beautify SQL:
+SELECT
+  sum(x) OVER (w1 ORDER BY
+    ts ROWS BETWEEN 1 PRECEDING AND CURRENT ROW) AS rolling_sum,
+  avg(x) OVER (w2) AS avg_over_w2
+FROM
+  t
+WINDOW w1 AS (PARTITION BY team), w2 AS (w1 ORDER BY
+  ts ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW);

parser/testdata/query/format/select_window_keyword_name_in_parens.sql

@@ -0,0 +1,8 @@
+-- Origin SQL:
+SELECT sum(x) OVER (order) AS sum_over_order
+FROM t
+WINDOW order AS (PARTITION BY team ORDER BY ts);
+
+
+-- Format SQL:
+SELECT sum(x) OVER (order) AS sum_over_order FROM t WINDOW order AS (PARTITION BY team ORDER BY ts);

parser/testdata/query/format/select_window_named_in_parens.sql

@@ -0,0 +1,8 @@
+-- Origin SQL:
+SELECT sum(x) OVER (w) AS sum_over_w
+FROM t
+WINDOW w AS (PARTITION BY y ORDER BY x);
+
+
+-- Format SQL:
+SELECT sum(x) OVER (w) AS sum_over_w FROM t WINDOW w AS (PARTITION BY y ORDER BY x);

parser/testdata/query/format/select_window_named_reference_extensions.sql

@@ -0,0 +1,10 @@
+-- Origin SQL:
+SELECT sum(x) OVER (w1 ORDER BY ts ROWS BETWEEN 1 PRECEDING AND CURRENT ROW) AS rolling_sum,
+       avg(x) OVER (w2)                                                      AS avg_over_w2
+FROM t
+WINDOW w1 AS (PARTITION BY team),
+       w2 AS (w1 ORDER BY ts ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW);
+
+
+-- Format SQL:
+SELECT sum(x) OVER (w1 ORDER BY ts ROWS BETWEEN 1 PRECEDING AND CURRENT ROW) AS rolling_sum, avg(x) OVER (w2) AS avg_over_w2 FROM t WINDOW w1 AS (PARTITION BY team), w2 AS (w1 ORDER BY ts ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW);