diff --git a/expression/constant_propagation.go b/expression/constant_propagation.go
index 264bb0dd5494a..f236ad722b3d0 100644
--- a/expression/constant_propagation.go
+++ b/expression/constant_propagation.go
@@ -228,7 +228,8 @@ func (s *propConstSolver) propagateColumnEQ() {
 		if fun, ok := s.conditions[i].(*ScalarFunction); ok && fun.FuncName.L == ast.EQ {
 			lCol, lOk := fun.GetArgs()[0].(*Column)
 			rCol, rOk := fun.GetArgs()[1].(*Column)
-			if lOk && rOk && lCol.GetType().Collate == rCol.GetType().Collate {
+			// TODO: Enable hybrid types in ConstantPropagate.
+			if lOk && rOk && lCol.GetType().Collate == rCol.GetType().Collate && !lCol.GetType().Hybrid() && !rCol.GetType().Hybrid() {
 				lID := s.getColID(lCol)
 				rID := s.getColID(rCol)
 				s.unionSet.Union(lID, rID)
@@ -301,6 +302,10 @@ func (s *propConstSolver) pickNewEQConds(visited []bool) (retMapper map[int]*Con
 			}
 			continue
 		}
+		// TODO: Enable hybrid types in ConstantPropagate.
+		if col.GetType().Hybrid() {
+			continue
+		}
 		visited[i] = true
 		updated, foreverFalse := s.tryToUpdateEQList(col, con)
 		if foreverFalse {
diff --git a/expression/integration_test.go b/expression/integration_test.go
index 2f183607a47ce..69b62de08e757 100755
--- a/expression/integration_test.go
+++ b/expression/integration_test.go
@@ -7077,3 +7077,22 @@ func (s *testIntegrationSuite) TestIssue17476(c *C) {
 	tk.MustQuery(`SELECT count(*) FROM (table_float JOIN table_int_float_varchar AS tmp3 ON (tmp3.col_varchar_6 AND NULL) IS NULL);`).Check(testkit.Rows("154"))
 	tk.MustQuery(`SELECT * FROM (table_int_float_varchar AS tmp3) WHERE (col_varchar_6 AND NULL) IS NULL AND col_int_6=0;`).Check(testkit.Rows("13 0 -0.1 <nil>"))
 }
+
+func (s *testIntegrationSuite) TestIssue20180(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("use test")
+	tk.MustExec("drop table if exists t;")
+	tk.MustExec("drop table if exists t1;")
+	tk.MustExec("create table t(a enum('a', 'b'), b tinyint);")
+	tk.MustExec("create table t1(c varchar(20));")
+	tk.MustExec("insert into t values('b', 0);")
+	tk.MustExec("insert into t1 values('b');")
+	tk.MustQuery("select * from t, t1 where t.a= t1.c;").Check(testkit.Rows("b 0 b"))
+	tk.MustQuery("select * from t, t1 where t.b= t1.c;").Check(testkit.Rows("b 0 b"))
+	tk.MustQuery("select * from t, t1 where t.a = t1.c and t.b= t1.c;").Check(testkit.Rows("b 0 b"))
+
+	tk.MustExec("drop table if exists t;")
+	tk.MustExec("create table t(a enum('a','b'));")
+	tk.MustExec("insert into t values('b');")
+	tk.MustQuery("select * from t where a > 1  and a = \"b\";").Check(testkit.Rows("b"))
+}