parser: support sql_mode "PIPES_AS_CONCAT"

mysql/const.go

@@ -427,6 +427,11 @@ func (m SQLMode) HasStrictMode() bool {
 	return m&ModeStrictTransTables == ModeStrictTransTables || m&ModeStrictAllTables == ModeStrictAllTables
 }
 
+// HasPipesAsConcatMode detects if 'PIPES_AS_CONCAT' mode is set in SQLMode
+func (m SQLMode) HasPipesAsConcatMode() bool {
+	return m&ModePipesAsConcat == ModePipesAsConcat
+}
+
 // HasRealAsFloatMode detects if 'REAL_AS_FLOAT' mode is set in SQLMode
 func (m SQLMode) HasRealAsFloatMode() bool {
 	return m&ModeRealAsFloat == ModeRealAsFloat

mysql/const_test.go

@@ -148,3 +148,10 @@ func (s *testMySQLConstSuite) TestRealAsFloatMode(c *C) {
 	row = result.Rows()[0]
 	c.Assert(row[1], Equals, "float")
 }
+
+func (s *testMySQLConstSuite) TestPipesAsConcatMode(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("SET sql_mode='PIPES_AS_CONCAT';")
+	r := tk.MustQuery(`SELECT 'hello' || 'world';`)
+	r.Check(testkit.Rows("helloworld"))
+}

parser/lexer.go

@@ -146,6 +146,10 @@ func (s *Scanner) Lex(v *yySymType) int {
 		tok = identifier
 	}
 
+	if tok == oror && !(s.sqlMode.HasPipesAsConcatMode()) {
+		return or2
+	}
+
 	switch tok {
 	case intLit:
 		return toInt(s, v, lit)

parser/parser.y

@@ -434,6 +434,8 @@ import (
 	paramMarker	"?"
 	rsh		">>"
 
+%token<ident> or2
+
 %type	<expr>
 	Expression			"expression"
 	BoolPri				"boolean primary expression"
@@ -781,7 +783,7 @@ import (
 %precedence lowerThanOn
 %precedence on using
 %right   assignmentEq
-%left 	oror or
+%left 	oror or or2
 %left 	xor
 %left 	andand and
 %left 	between
@@ -1896,7 +1898,8 @@ Expression:
 
 
 logOr:
-"||" | "OR"
+    or2
+|   "OR"
 
 logAnd:
 "&&" | "AND"
@@ -1986,7 +1989,7 @@ CompareOp:
 |	"<>"
 	{
 		$$ = opcode.NE
-	}
+    }
 |	"="
 	{
 		$$ = opcode.EQ
@@ -2767,6 +2770,10 @@ SimpleExpr:
 	{
 		$$ = &ast.UnaryOperationExpr{Op: opcode.Plus, V: $2}
 	}
+|   SimpleExpr oror	SimpleExpr
+    {
+		$$ = &ast.FuncCallExpr{FnName: model.NewCIStr(ast.Concat), Args: []ast.ExprNode{$1, $3}}
+    }
 |	SubSelect
 |	'(' Expression ')' {
 		startOffset := parser.startOffset(&yyS[yypt-1])
@@ -5456,6 +5463,9 @@ DateAndTimeType:
 		x := types.NewFieldType(mysql.TypeTimestamp)
 		x.Flen = mysql.MaxDatetimeWidthNoFsp
 		x.Decimal = $2.(int)
+		if x.Decimal == types.UnspecifiedLength{
+		    x.Decimal = 0
+		}
 		if x.Decimal > 0 {
 			x.Flen = x.Flen + 1 + x.Decimal
 		}