planner, executor: fix tp.Flen size when union with castIntAsString (#…

…8442)
pingcap · Nov 27, 2018 · 487bb50 · 487bb50
1 parent 0ac0e15
commit 487bb50
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diff --git a/executor/executor_test.go b/executor/executor_test.go
@@ -1102,6 +1102,12 @@ func (s *testSuite) TestUnion(c *C) {
 	for i := 0; i < 4; i++ {
 		tk.MustQuery("SELECT(SELECT 0 AS a FROM dual UNION SELECT 1 AS a FROM dual ORDER BY a ASC  LIMIT 1) AS dev").Check(testkit.Rows("0"))
 	}
+
+	// #issue 8231
+	tk.MustExec("drop table if exists t1")
+	tk.MustExec("CREATE TABLE t1 (uid int(1))")
+	tk.MustExec("INSERT INTO t1 SELECT 150")
+	tk.MustQuery("SELECT 'a' UNION SELECT uid FROM t1 order by 1 desc;").Check(testkit.Rows("a", "150"))
 }
 
 func (s *testSuite) TestNeighbouringProj(c *C) {

diff --git a/planner/core/logical_plan_builder.go b/planner/core/logical_plan_builder.go
@@ -659,6 +659,9 @@ func unionJoinFieldType(a, b *types.FieldType) *types.FieldType {
 	resultTp.Decimal = mathutil.Max(a.Decimal, b.Decimal)
 	// `Flen - Decimal` is the fraction before '.'
 	resultTp.Flen = mathutil.Max(a.Flen-a.Decimal, b.Flen-b.Decimal) + resultTp.Decimal
+	if resultTp.EvalType() != types.ETInt && (a.EvalType() == types.ETInt || b.EvalType() == types.ETInt) && resultTp.Flen < mysql.MaxIntWidth {
+		resultTp.Flen = mysql.MaxIntWidth
+	}
 	resultTp.Charset = a.Charset
 	resultTp.Collate = a.Collate
 	expression.SetBinFlagOrBinStr(b, resultTp)