Implement group hints (#341)

Author: apstndb

ast/ast.go

@@ -992,13 +992,14 @@ type Where struct {
 
 // GroupBy is GROUP BY clause node.
 //
-//	GROUP BY {{.Exprs | sqlJoin ","}}
+//	GROUP {{.Hint | sqlOpt}} BY {{.Exprs | sqlJoin ","}}
 type GroupBy struct {
 	// pos = Group
 	// end = Exprs[$].end
 
 	Group token.Pos // position of "GROUP" keyword
 
+	Hint  *Hint  // optional
 	Exprs []Expr // len(Exprs) > 0
 }
 
@@ -2302,7 +2303,6 @@ type DropSchema struct {
 	Name     *Ident
 }
 
-
 // CreateDatabase is CREATE DATABASE statement node.
 //
 //	CREATE DATABASE {{.Name | sql}}

ast/sql.go

@@ -281,7 +281,7 @@ func (w *Where) SQL() string {
 }
 
 func (g *GroupBy) SQL() string {
-	return "GROUP BY " + sqlJoin(g.Exprs, ", ")
+	return "GROUP " + sqlOpt("", g.Hint, " ") + "BY " + sqlJoin(g.Exprs, ", ")
 }
 
 func (h *Having) SQL() string {
@@ -776,7 +776,9 @@ func (s *CreateSchema) SQL() string {
 	return "CREATE" + strOpt(s.OrReplace, " OR REPLACE") + " SCHEMA " + strOpt(s.IfNotExists, "IF NOT EXISTS ") + s.Name.SQL()
 }
 
-func (s *DropSchema) SQL() string { return "DROP SCHEMA " + strOpt(s.IfExists, "IF EXISTS ") + s.Name.SQL() }
+func (s *DropSchema) SQL() string {
+	return "DROP SCHEMA " + strOpt(s.IfExists, "IF EXISTS ") + s.Name.SQL()
+}
 
 func (d *AlterDatabase) SQL() string {
 	return "ALTER DATABASE " + d.Name.SQL() + " SET " + d.Options.SQL()

ast/walk_internal.go

@@ -794,11 +794,13 @@ func (p *Parser) tryParseGroupBy() *ast.GroupBy {
 		return nil
 	}
 	pos := p.expect("GROUP").Pos
+	hint := p.tryParseHint()
 	p.expect("BY")
 	exprs := parseCommaSeparatedList(p, p.parseExpr)
 
 	return &ast.GroupBy{
 		Group: pos,
+		Hint:  hint,
 		Exprs: exprs,
 	}
 }

parser.go

@@ -0,0 +1,6 @@
+SELECT
+  FirstName, BirthDate
+FROM
+  Singers
+GROUP @{GROUP_METHOD=HASH_GROUP} BY
+  FirstName, BirthDate

testdata/input/query/select_singer_with_groupby_group_hints.sql

@@ -0,0 +1,79 @@
+--- select_singer_with_groupby_group_hints.sql
+SELECT
+  FirstName, BirthDate
+FROM
+  Singers
+GROUP @{GROUP_METHOD=HASH_GROUP} BY
+  FirstName, BirthDate
+
+--- AST
+&ast.QueryStatement{
+  Query: &ast.Select{
+    Results: []ast.SelectItem{
+      &ast.ExprSelectItem{
+        Expr: &ast.Ident{
+          NamePos: 9,
+          NameEnd: 18,
+          Name:    "FirstName",
+        },
+      },
+      &ast.ExprSelectItem{
+        Expr: &ast.Ident{
+          NamePos: 20,
+          NameEnd: 29,
+          Name:    "BirthDate",
+        },
+      },
+    },
+    From: &ast.From{
+      From:   30,
+      Source: &ast.TableName{
+        Table: &ast.Ident{
+          NamePos: 37,
+          NameEnd: 44,
+          Name:    "Singers",
+        },
+      },
+    },
+    GroupBy: &ast.GroupBy{
+      Group: 45,
+      Hint:  &ast.Hint{
+        Atmark:  51,
+        Rbrace:  76,
+        Records: []*ast.HintRecord{
+          &ast.HintRecord{
+            Key: &ast.Path{
+              Idents: []*ast.Ident{
+                &ast.Ident{
+                  NamePos: 53,
+                  NameEnd: 65,
+                  Name:    "GROUP_METHOD",
+                },
+              },
+            },
+            Value: &ast.Ident{
+              NamePos: 66,
+              NameEnd: 76,
+              Name:    "HASH_GROUP",
+            },
+          },
+        },
+      },
+      Exprs: []ast.Expr{
+        &ast.Ident{
+          NamePos: 83,
+          NameEnd: 92,
+          Name:    "FirstName",
+        },
+        &ast.Ident{
+          NamePos: 94,
+          NameEnd: 103,
+          Name:    "BirthDate",
+        },
+      },
+    },
+  },
+}
+
+--- SQL
+SELECT FirstName, BirthDate FROM Singers GROUP @{GROUP_METHOD=HASH_GROUP} BY FirstName, BirthDate

testdata/result/query/select_singer_with_groupby_group_hints.sql.txt

@@ -0,0 +1,79 @@
+--- select_singer_with_groupby_group_hints.sql
+SELECT
+  FirstName, BirthDate
+FROM
+  Singers
+GROUP @{GROUP_METHOD=HASH_GROUP} BY
+  FirstName, BirthDate
+
+--- AST
+&ast.QueryStatement{
+  Query: &ast.Select{
+    Results: []ast.SelectItem{
+      &ast.ExprSelectItem{
+        Expr: &ast.Ident{
+          NamePos: 9,
+          NameEnd: 18,
+          Name:    "FirstName",
+        },
+      },
+      &ast.ExprSelectItem{
+        Expr: &ast.Ident{
+          NamePos: 20,
+          NameEnd: 29,
+          Name:    "BirthDate",
+        },
+      },
+    },
+    From: &ast.From{
+      From:   30,
+      Source: &ast.TableName{
+        Table: &ast.Ident{
+          NamePos: 37,
+          NameEnd: 44,
+          Name:    "Singers",
+        },
+      },
+    },
+    GroupBy: &ast.GroupBy{
+      Group: 45,
+      Hint:  &ast.Hint{
+        Atmark:  51,
+        Rbrace:  76,
+        Records: []*ast.HintRecord{
+          &ast.HintRecord{
+            Key: &ast.Path{
+              Idents: []*ast.Ident{
+                &ast.Ident{
+                  NamePos: 53,
+                  NameEnd: 65,
+                  Name:    "GROUP_METHOD",
+                },
+              },
+            },
+            Value: &ast.Ident{
+              NamePos: 66,
+              NameEnd: 76,
+              Name:    "HASH_GROUP",
+            },
+          },
+        },
+      },
+      Exprs: []ast.Expr{
+        &ast.Ident{
+          NamePos: 83,
+          NameEnd: 92,
+          Name:    "FirstName",
+        },
+        &ast.Ident{
+          NamePos: 94,
+          NameEnd: 103,
+          Name:    "BirthDate",
+        },
+      },
+    },
+  },
+}
+
+--- SQL
+SELECT FirstName, BirthDate FROM Singers GROUP @{GROUP_METHOD=HASH_GROUP} BY FirstName, BirthDate