planner, util/ranger: fix wrong optimize order by (#30273) (#30551)

close #30271

planner/core/integration_test.go

@@ -4359,3 +4359,16 @@ func (s *testIntegrationSuite) TestIssue27797(c *C) {
  result = tk.MustQuery("select col2 from IDT_HP24172 where col1 = 8388607 and col1 in (select col1 from IDT_HP24172);")
  result.Check(testkit.Rows("<nil>"))
 }
+
+func (s *testIntegrationSerialSuite) TestIssue30271(c *C) {
+ defer collate.SetNewCollationEnabledForTest(false)
+ collate.SetNewCollationEnabledForTest(true)
+ tk := testkit.NewTestKit(c, s.store)
+ tk.MustExec("use test")
+ tk.MustExec("drop table if exists t")
+ tk.MustExec("create table t(a char(10), b char(10), c char(10), index (a, b, c)) collate utf8mb4_bin;")
+ tk.MustExec("insert into t values ('b', 'a', '1'), ('b', 'A', '2'), ('c', 'a', '3');")
+ tk.MustExec("set names utf8mb4 collate utf8mb4_general_ci;")
+ tk.MustQuery("select * from t where (a>'a' and b='a') or (b = 'A' and a < 'd') order by a,c;").Check(testkit.Rows("b a 1", "b A 2", "c a 3"))
+
+}

util/ranger/detacher.go

@@ -18,6 +18,7 @@ import (
 
  "github.com/pingcap/errors"
  "github.com/pingcap/parser/ast"
+ "github.com/pingcap/parser/charset"
  "github.com/pingcap/parser/model"
  "github.com/pingcap/tidb/expression"
  "github.com/pingcap/tidb/sessionctx"
@@ -704,7 +705,11 @@ func isSameValue(sc *stmtctx.StatementContext, lhs, rhs *valueInfo) (bool, error
  if lhs == nil || rhs == nil || lhs.mutable || rhs.mutable || lhs.value.Kind() != rhs.value.Kind() {
  return false, nil
  }
+ collation := lhs.value.Collation()
+ // binary collator may not the best choice, but it can make sure the result is correct.
+ lhs.value.SetCollation(charset.CollationBin)
  cmp, err := lhs.value.CompareDatum(sc, rhs.value)
+ lhs.value.SetCollation(collation)
  if err != nil {
  return false, err
  }