diff --git a/src/sql/engine/expr/ob_expr_operator.cpp b/src/sql/engine/expr/ob_expr_operator.cpp
index 058ce197de..d6fe19633a 100644
--- a/src/sql/engine/expr/ob_expr_operator.cpp
+++ b/src/sql/engine/expr/ob_expr_operator.cpp
@@ -1029,7 +1029,7 @@ int ObExprOperator::is_same_kind_type_for_case(const ObExprResType &type1, const
   return ret;
 }
 
-// coaesce expr, case when expr
+// coalesce expr, case when expr
 int ObExprOperator::aggregate_result_type_for_case(
   ObExprResType &type,
   const ObExprResType *types,
@@ -1057,12 +1057,14 @@ int ObExprOperator::aggregate_result_type_for_case(
     }
     nth = OB_INVALID_ID == nth ? 0 : nth;
     const ObExprResType &res_type = types[nth];
-    if (need_merge_type && lib::is_oracle_mode() && ObTinyIntType == types[0].get_type()) {
+    if (need_merge_type && lib::is_oracle_mode() && is_called_in_sql
+        && ObTinyIntType == types[0].get_type()) {
       ret = OB_ERR_CALL_WRONG_ARG;
       LOG_WARN("PLS-00306: wrong number or types of arguments in call", K(ret));
     }
     for (int64_t i = 1; OB_SUCC(ret) && i < param_num; ++i) {
-      if (need_merge_type && lib::is_oracle_mode() && ObTinyIntType == types[i].get_type()) {
+      if (need_merge_type && lib::is_oracle_mode() && is_called_in_sql
+          && ObTinyIntType == types[i].get_type()) {
         ret = OB_ERR_CALL_WRONG_ARG;
         LOG_WARN("PLS-00306: wrong number or types of arguments in call", K(ret));
       } else if (OB_FAIL(ObExprOperator::is_same_kind_type_for_case(res_type,
@@ -1075,7 +1077,15 @@ int ObExprOperator::aggregate_result_type_for_case(
     }
   }
   if (OB_SUCC(ret)) {
-    if (OB_FAIL(aggregate_result_type_for_merge(type, types, param_num, conn_coll_type,
+    if (need_merge_type && lib::is_oracle_mode() && ObTinyIntType == types[0].get_type()) {
+      // bypass `aggregate_result_type_for_merge()` when oracle `case expression` returns boolean,
+      // also known as ObTinyIntType. `aggregate_result_type_for_merge()` would merge
+      // ObTinyIntType into ObInt32Type.
+      type.set_type(ObTinyIntType);
+      if (OB_FAIL(aggregate_numeric_accuracy_for_merge(type, types, param_num, is_oracle_mode))) {
+        LOG_WARN("fail to aggregate numeric accuracy", K(ret));
+      }
+    } else if (OB_FAIL(aggregate_result_type_for_merge(type, types, param_num, conn_coll_type,
         is_oracle_mode, default_length_semantics, session, need_merge_type, skip_null,
         is_called_in_sql))) {
       LOG_WARN("fail to aggregate result type", K(ret));
diff --git a/src/sql/rewrite/ob_transform_pre_process.cpp b/src/sql/rewrite/ob_transform_pre_process.cpp
index 08edb0ceb9..01aeb4ff2a 100644
--- a/src/sql/rewrite/ob_transform_pre_process.cpp
+++ b/src/sql/rewrite/ob_transform_pre_process.cpp
@@ -32,6 +32,7 @@
 #include "sql/session/ob_sql_session_info.h"
 #include "share/config/ob_server_config.h"
 #include "sql/rewrite/ob_transform_utils.h"
+#include "sql/resolver/dml/ob_insert_all_stmt.h"
 #include "sql/resolver/dml/ob_select_stmt.h"
 #include "sql/resolver/dml/ob_select_resolver.h"
 #include "sql/resolver/dml/ob_merge_stmt.h"
@@ -5346,6 +5347,12 @@ int ObTransformPreProcess::transform_arg_case_expr(ObRawExprFactory &expr_factor
       LOG_WARN("failed to add param expr", K(ret));
     }
   } // for end
+  ObRawExpr* tmp_case_expr = static_cast<ObRawExpr*>(new_case_expr);
+  if (OB_SUCC(ret) &&
+      !case_expr->is_called_in_sql() &&
+      OB_FAIL(ObRawExprUtils::set_call_in_pl(tmp_case_expr))) {
+    LOG_WARN("failed to set call_in_pl flag", K(ret));
+  }
   if (OB_SUCC(ret)) {
     new_case_expr->set_default_param_expr(case_expr->get_default_param_expr());
     if (OB_FAIL(new_case_expr->formalize(&session))) {