expression: correct constant propagation for collation (#22666)

Signed-off-by: wjhuang2016 <huangwenjun1997@gmail.com>
pingcap · Feb 24, 2021 · eea52f5 · eea52f5
1 parent e360454
commit eea52f5
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Showing 2 changed files with 8 additions and 2 deletions.
diff --git a/expression/constant_propagation.go b/expression/constant_propagation.go
@@ -20,7 +20,6 @@ import (
  "github.com/pingcap/tidb/sessionctx"
  "github.com/pingcap/tidb/types"
  "github.com/pingcap/tidb/util/chunk"
- "github.com/pingcap/tidb/util/collate"
  "github.com/pingcap/tidb/util/disjointset"
  "github.com/pingcap/tidb/util/logutil"
  "go.uber.org/zap"
@@ -88,7 +87,7 @@ func validEqualCondHelper(ctx sessionctx.Context, eq *ScalarFunction, colIsLeft
  if ContainMutableConst(ctx, []Expression{con}) {
  return nil, nil
  }
- if !collate.CompatibleCollate(col.GetType().Collate, con.GetType().Collate) {
+ if col.GetType().Collate != con.GetType().Collate {
  return nil, nil
  }
  return col, con

diff --git a/expression/integration_test.go b/expression/integration_test.go
@@ -6412,6 +6412,13 @@ func (s *testIntegrationSerialSuite) TestCollateConstantPropagation(c *C) {
  tk.MustExec("insert into t1 values ('ß', 's');")
  tk.MustExec("insert into t2 values ('s', 's')")
  tk.MustQuery("select * from t1 left join t2 on t1.a = t2.a collate utf8mb4_unicode_ci where t1.a = 's';").Check(testkit.Rows("ß s <nil> <nil>"))
+ tk.MustExec("drop table if exists t1, t2;")
+ tk.MustExec("create table t1(a char(10) collate utf8mb4_general_ci, index (a));")
+ tk.MustExec("create table t2(a char(10) collate utf8_bin, index (a));")
+ tk.MustExec("insert into t1 values ('a');")
+ tk.MustExec("insert into t2 values ('A');")
+ tk.MustExec("set names utf8 collate utf8_general_ci;")
+ tk.MustQuery("select * from t1, t2 where t1.a=t2.a and t1.a= 'a';").Check(testkit.Rows("a A"))
 }
 
 func (s *testIntegrationSuite2) TestIssue17791(c *C) {