expression: fix type infer of unaryMinus which should return ETDecima…

…l if ETInt overflow int (#11989) (#11991)
pingcap · Sep 2, 2019 · ddf2411 · ddf2411
1 parent 2b99cdd
commit ddf2411
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Showing 2 changed files with 9 additions and 4 deletions.
diff --git a/expression/builtin_op.go b/expression/builtin_op.go
@@ -642,16 +642,15 @@ func (c *unaryMinusFunctionClass) handleIntOverflow(arg *Constant) (overflow boo
 
 // typeInfer infers unaryMinus function return type. when the arg is an int constant and overflow,
 // typerInfer will infers the return type as types.ETDecimal, not types.ETInt.
-func (c *unaryMinusFunctionClass) typeInfer(ctx sessionctx.Context, argExpr Expression) (types.EvalType, bool) {
+func (c *unaryMinusFunctionClass) typeInfer(argExpr Expression) (types.EvalType, bool) {
 	tp := argExpr.GetType().EvalType()
 	if tp != types.ETInt && tp != types.ETDecimal {
 		tp = types.ETReal
 	}
 
-	sc := ctx.GetSessionVars().StmtCtx
 	overflow := false
 	// TODO: Handle float overflow.
-	if arg, ok := argExpr.(*Constant); sc.InSelectStmt && ok && tp == types.ETInt {
+	if arg, ok := argExpr.(*Constant); ok && tp == types.ETInt {
 		overflow = c.handleIntOverflow(arg)
 		if overflow {
 			tp = types.ETDecimal
@@ -666,7 +665,7 @@ func (c *unaryMinusFunctionClass) getFunction(ctx sessionctx.Context, args []Exp
 	}
 
 	argExpr, argExprTp := args[0], args[0].GetType()
-	_, intOverflow := c.typeInfer(ctx, argExpr)
+	_, intOverflow := c.typeInfer(argExpr)
 
 	var bf baseBuiltinFunc
 	switch argExprTp.EvalType() {

diff --git a/expression/integration_test.go b/expression/integration_test.go
@@ -2080,6 +2080,12 @@ func (s *testIntegrationSuite) TestOpBuiltin(c *C) {
 	// for unaryPlus
 	result = tk.MustQuery(`select +1, +0, +(-9), +(-0.001), +0.999, +null, +"aaa"`)
 	result.Check(testkit.Rows("1 0 -9 -0.001 0.999 <nil> aaa"))
+	// for unaryMinus
+	tk.MustExec("drop table if exists f")
+	tk.MustExec("create table f(a decimal(65,0))")
+	tk.MustExec("insert into f value (-17000000000000000000)")
+	result = tk.MustQuery("select a from f")
+	result.Check(testkit.Rows("-17000000000000000000"))
 }
 
 func (s *testIntegrationSuite) TestDatetimeOverflow(c *C) {