diff --git a/src/sql/engine/expr/ob_expr_extract.cpp b/src/sql/engine/expr/ob_expr_extract.cpp
index 671a195718..9b049f8039 100644
--- a/src/sql/engine/expr/ob_expr_extract.cpp
+++ b/src/sql/engine/expr/ob_expr_extract.cpp
@@ -29,7 +29,7 @@ using namespace common;
 namespace sql
 {
 ObExprExtract::ObExprExtract(ObIAllocator &alloc)
-    : ObFuncExprOperator(alloc, T_FUN_SYS_EXTRACT, N_EXTRACT, 2, NOT_VALID_FOR_GENERATED_COL, NOT_ROW_DIMENSION)
+    : ObFuncExprOperator(alloc, T_FUN_SYS_EXTRACT, N_EXTRACT, 2, VALID_FOR_GENERATED_COL, NOT_ROW_DIMENSION)
 {
 }
 
diff --git a/src/sql/engine/expr/ob_expr_oracle_to_char.cpp b/src/sql/engine/expr/ob_expr_oracle_to_char.cpp
index c818681ca8..8f52721fd3 100644
--- a/src/sql/engine/expr/ob_expr_oracle_to_char.cpp
+++ b/src/sql/engine/expr/ob_expr_oracle_to_char.cpp
@@ -152,7 +152,7 @@ int ObExprOracleToChar::calc_result_typeN(ObExprResType &type,
     if (type_array[0].is_oracle_temporal_type()) {
       type_array[1].set_calc_type(ObVarcharType);
       type_array[1].set_calc_collation_type(nls_param.nls_collation_);
-    } else {
+    } else if (!type_array[1].is_varchar_or_char()) {
       type_array[1].set_calc_type_default_varchar();
     }
   }
diff --git a/src/sql/resolver/expr/ob_raw_expr_util.cpp b/src/sql/resolver/expr/ob_raw_expr_util.cpp
index 808bdc7858..6d19c8001c 100644
--- a/src/sql/resolver/expr/ob_raw_expr_util.cpp
+++ b/src/sql/resolver/expr/ob_raw_expr_util.cpp
@@ -1985,17 +1985,6 @@ int ObRawExprUtils::build_generated_column_expr(const obrpc::ObCreateIndexArg *a
   if (OB_SUCC(ret)) {
     if (OB_FAIL(expr->formalize(&session_info))) {
       LOG_WARN("formalize expr failed", K(ret), KPC(expr));
-    } else if (ObResolverUtils::CHECK_FOR_FUNCTION_INDEX == check_status ||
-               ObResolverUtils::CHECK_FOR_GENERATED_COLUMN == check_status) {
-      if (OB_FAIL(ObRawExprUtils::check_is_valid_generated_col(expr, expr_factory.get_allocator()))) {
-        if (OB_ERR_ONLY_PURE_FUNC_CANBE_VIRTUAL_COLUMN_EXPRESSION == ret
-                 && ObResolverUtils::CHECK_FOR_FUNCTION_INDEX == check_status) {
-          ret = OB_ERR_ONLY_PURE_FUNC_CANBE_INDEXED;
-          LOG_WARN("sysfunc in expr is not valid for generated column", K(ret), K(*expr));
-        } else {
-          LOG_WARN("fail to check if the sysfunc exprs are valid in generated columns", K(ret));
-        }
-      }
     }
   }
 
diff --git a/src/sql/rewrite/ob_transform_pre_process.cpp b/src/sql/rewrite/ob_transform_pre_process.cpp
index 2aa04e7376..0001f77bbe 100644
--- a/src/sql/rewrite/ob_transform_pre_process.cpp
+++ b/src/sql/rewrite/ob_transform_pre_process.cpp
@@ -8450,7 +8450,9 @@ int ObTransformPreProcess::transform_rollup_exprs(ObDMLStmt *stmt, bool &trans_h
     } else if (expr->has_flag(CNT_VOLATILE_CONST) || !expr->is_const_expr()) {
       //do nothing
     } else if (expr->is_static_const_expr()) { //static const expr
-      if (OB_FAIL(ObRawExprUtils::build_remove_const_expr(
+      if (ObOptimizerUtil::find_item(static_const_exprs, expr)) {
+        //do nothing, skip dup exprs
+      } else if (OB_FAIL(ObRawExprUtils::build_remove_const_expr(
                                         *ctx_->expr_factory_,
                                         *ctx_->session_info_,
                                         expr,
@@ -8467,6 +8469,8 @@ int ObTransformPreProcess::transform_rollup_exprs(ObDMLStmt *stmt, bool &trans_h
         stmt->get_rollup_exprs().at(i) = remove_const_expr;
         trans_happened = true;
       }
+    }  else if (ObOptimizerUtil::find_item(exec_param_exprs, expr)) {
+      //do nothing, skip dup exprs
     } else if (OB_FAIL(ObRawExprUtils::build_remove_const_expr(
                                       *ctx_->expr_factory_,
                                       *ctx_->session_info_,