diff --git a/src/sql/rewrite/ob_transform_join_elimination.cpp b/src/sql/rewrite/ob_transform_join_elimination.cpp
index e5097612bd..9b31cb732d 100644
--- a/src/sql/rewrite/ob_transform_join_elimination.cpp
+++ b/src/sql/rewrite/ob_transform_join_elimination.cpp
@@ -2074,22 +2074,20 @@ int ObTransformJoinElimination::trans_column_expr(ObDMLStmt* stmt, ObRawExpr* ex
 {
   int ret = OB_SUCCESS;
   new_expr = NULL;
+  bool is_nullable = false;
   if (OB_ISNULL(stmt) || OB_ISNULL(expr) || OB_ISNULL(ctx_)) {
-    LOG_WARN("param has null", K(ret));
+    LOG_WARN("param has null", K(ret), K(stmt), K(expr), K(ctx_));
+  } else if (OB_FAIL(ObTransformUtils::check_expr_nullable(stmt, expr, is_nullable, ObTransformUtils::NULLABLE_SCOPE::NS_FROM))) {
+    LOG_WARN("failed to check whether expr is nullable", K(ret));
+  } else if (!is_nullable) {
+    if (OB_FAIL(ObRawExprUtils::build_const_bool_expr(ctx_->expr_factory_, new_expr, true))) {
+      LOG_WARN("build true expr failed", K(ret));
+    } else { /*do nothing*/
+    }
   } else {
-    bool is_nullable = false;
-    if (OB_FAIL(ObTransformUtils::check_expr_nullable(stmt, expr, is_nullable))) {
-      LOG_WARN("failed to check whether expr is nullable", K(ret));
-    } else if (!is_nullable) {
-      if (OB_FAIL(ObRawExprUtils::build_const_bool_expr(ctx_->expr_factory_, new_expr, true))) {
-        LOG_WARN("build true expr failed", K(ret));
-      } else { /*do nothing*/
-      }
-    } else {
-      if (OB_FAIL(ObRawExprUtils::build_is_not_null_expr(*ctx_->expr_factory_, expr, new_expr))) {
-        LOG_WARN("build is not null expr failed", K(ret));
-      } else { /*do nothing*/
-      }
+    if (OB_FAIL(ObRawExprUtils::build_is_not_null_expr(*ctx_->expr_factory_, expr, new_expr))) {
+      LOG_WARN("build is not null expr failed", K(ret));
+    } else { /*do nothing*/
     }
   }
   return ret;
diff --git a/src/sql/rewrite/ob_transform_utils.cpp b/src/sql/rewrite/ob_transform_utils.cpp
index c4f9dfc734..b1951d83f9 100644
--- a/src/sql/rewrite/ob_transform_utils.cpp
+++ b/src/sql/rewrite/ob_transform_utils.cpp
@@ -1743,7 +1743,7 @@ int ObTransformUtils::find_not_null_expr(ObDMLStmt& stmt, ObRawExpr*& not_null_e
 
 // 1. check is there null rejecting condition
 // 2. check is nullable column, and is not the right table of outer join
-int ObTransformUtils::check_expr_nullable(ObDMLStmt* stmt, ObRawExpr* expr, bool& is_nullable)
+int ObTransformUtils::check_expr_nullable(ObDMLStmt* stmt, ObRawExpr* expr, bool& is_nullable, int nullable_scope /* = ObTransformUtils::NULLABLE_SCOPE::NS_WHERE */)
 {
   int ret = OB_SUCCESS;
   is_nullable = true;
@@ -1757,12 +1757,14 @@ int ObTransformUtils::check_expr_nullable(ObDMLStmt* stmt, ObRawExpr* expr, bool
     LOG_WARN("failed to check is not null column", K(ret));
   } else if (not_null_col) {
     is_nullable = false;
-  } else if (OB_FAIL(stmt->get_equal_set_conditions(valid_conds, true, SCOPE_WHERE))) {
-    LOG_WARN("failed to get equal set conditions", K(ret));
-  } else if (OB_FAIL(has_null_reject_condition(valid_conds, expr, has_null_reject))) {
-    LOG_WARN("failed to check has null reject condition", K(ret));
-  } else if (has_null_reject) {
-    is_nullable = false;
+  } else if (nullable_scope >= ObTransformUtils::NULLABLE_SCOPE::NS_WHERE) {
+    if (OB_FAIL(stmt->get_equal_set_conditions(valid_conds, true, SCOPE_WHERE))) {
+      LOG_WARN("failed to get equal set conditions", K(ret));
+    } else if (OB_FAIL(has_null_reject_condition(valid_conds, expr, has_null_reject))) {
+      LOG_WARN("failed to check has null reject condition", K(ret));
+    } else if (has_null_reject) {
+      is_nullable = false;
+    }
   }
   return ret;
 }
diff --git a/src/sql/rewrite/ob_transform_utils.h b/src/sql/rewrite/ob_transform_utils.h
index 3dd375dc4f..0a1d115cbc 100644
--- a/src/sql/rewrite/ob_transform_utils.h
+++ b/src/sql/rewrite/ob_transform_utils.h
@@ -242,7 +242,7 @@ public:
 
   static int find_not_null_expr(ObDMLStmt& stmt, ObRawExpr*& not_null_expr, bool& is_valid);
 
-  static int check_expr_nullable(ObDMLStmt* stmt, ObRawExpr* expr, bool& is_nullable);
+  static int check_expr_nullable(ObDMLStmt* stmt, ObRawExpr* expr, bool& is_nullable, int nullable_scope = ObTransformUtils::NULLABLE_SCOPE::NS_WHERE);
 
   static int check_is_not_null_column(const ObDMLStmt* stmt, const ObRawExpr* expr, bool& col_not_null);