diff --git a/executor/explain_test.go b/executor/explain_test.go
index a0ce1a1eb2e0c..ca7923e11049b 100644
--- a/executor/explain_test.go
+++ b/executor/explain_test.go
@@ -351,3 +351,24 @@ func (s *testSuite2) TestExplainAnalyzeCTEMemoryAndDiskInfo(c *C) {
 	c.Assert(rows[4][7].(string), Not(Equals), "N/A")
 	c.Assert(rows[4][8].(string), Not(Equals), "N/A")
 }
+
+func (s *testSuite) TestFix29401(c *C) {
+	tk := testkit.NewTestKitWithInit(c, s.store)
+	tk.MustExec("drop table if exists tt123;")
+	tk.MustExec(`CREATE TABLE tt123 (
+  id int(11) NOT NULL,
+  a bigint(20) DEFAULT NULL,
+  b char(20) DEFAULT NULL,
+  c datetime DEFAULT NULL,
+  d double DEFAULT NULL,
+  e json DEFAULT NULL,
+  f decimal(40,6) DEFAULT NULL,
+  PRIMARY KEY (id) /*T![clustered_index] CLUSTERED */,
+  KEY a (a),
+  KEY b (b),
+  KEY c (c),
+  KEY d (d),
+  KEY f (f)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin;`)
+	tk.MustExec(" explain select /*+ inl_hash_join(t1) */ * from tt123 t1 join tt123 t2 on t1.b=t2.e;")
+}
diff --git a/planner/core/rule_predicate_push_down.go b/planner/core/rule_predicate_push_down.go
index c4a350420b3ee..c49c7a21e73a3 100644
--- a/planner/core/rule_predicate_push_down.go
+++ b/planner/core/rule_predicate_push_down.go
@@ -286,10 +286,14 @@ func (p *LogicalProjection) appendExpr(expr expression.Expression) *expression.C
 
 	col := &expression.Column{
 		UniqueID: p.ctx.GetSessionVars().AllocPlanColumnID(),
-		RetType:  expr.GetType(),
+		RetType:  expr.GetType().Clone(),
 	}
 	col.SetCoercibility(expr.Coercibility())
 	p.schema.Append(col)
+	// reset ParseToJSONFlag in order to keep the flag away from json column
+	if col.GetType().Tp == mysql.TypeJSON {
+		col.GetType().Flag &= ^mysql.ParseToJSONFlag
+	}
 	return col
 }