diff --git a/src/sql/engine/expr/ob_expr_merge_result_type.map b/src/sql/engine/expr/ob_expr_merge_result_type.map
index 01b2aca079..14d6079946 100644
--- a/src/sql/engine/expr/ob_expr_merge_result_type.map
+++ b/src/sql/engine/expr/ob_expr_merge_result_type.map
@@ -50,7 +50,7 @@ static ObObjType MERGE_RESULT_TYPE[ObMaxType][ObMaxType] = {
         ObLobType,           /*NullType=>ObLobType*/
         ObJsonType,          /*NullType=>ObJsonType*/
         ObGeometryType,      /*NullType=>ObGeometryType*/
-        ObMaxType,           /*NullType=>ObUserDefinedSQLType*/
+        ObUserDefinedSQLType,/*NullType=>ObUserDefinedSQLType*/
     },
 
     /*TinyIntType*/
diff --git a/src/sql/ob_spi.cpp b/src/sql/ob_spi.cpp
index 1dc43a3da2..c07bc869be 100644
--- a/src/sql/ob_spi.cpp
+++ b/src/sql/ob_spi.cpp
@@ -2668,7 +2668,15 @@ int ObSPIService::spi_execute_immediate(ObPLExecCtx *ctx,
                       if (params[i]->is_pl_extend()) {
                         if (params[i]->get_meta().get_extend_type() != PL_REF_CURSOR_TYPE) {
                           new_param.set_int_value(0);
-                          OZ (pl::ObUserDefinedType::deep_copy_obj(allocator, *params[i], new_param, true));
+                          if (!ob_is_xml_pl_type(params[i]->get_type(), params[i]->get_udt_id())) {
+                            OZ (pl::ObUserDefinedType::deep_copy_obj(allocator, *params[i], new_param, true));
+                          } else {
+                            const ObDataTypeCastParams dtc_params = sql::ObBasicSessionInfo::create_dtc_params(ctx->exec_ctx_->get_my_session());
+                            ObCastCtx cast_ctx(ctx->allocator_, &dtc_params, CM_NONE, ObCharset::get_system_collation());
+                            if (OB_FAIL(ObObjCaster::to_type(ObUserDefinedSQLType, cast_ctx, *params[i], new_param))) {
+                              LOG_WARN("failed to_type", K(ret), K(new_param));
+                            }
+                          }
                         }
                       } else {
                         OZ (deep_copy_obj(allocator, *params[i], new_param));
@@ -5157,6 +5165,14 @@ int ObSPIService::construct_exec_params(ObPLExecCtx *ctx,
       } else if (result.is_ext()) {
         if (result_type.is_ext()) {
           OX (result.set_udt_id(result_type.get_udt_id()));
+          // xml pl type add cast
+          if (ob_is_xml_pl_type(result_type.get_type(), result_type.get_udt_id())) {
+            const ObDataTypeCastParams dtc_params = sql::ObBasicSessionInfo::create_dtc_params(ctx->exec_ctx_->get_my_session());
+            ObCastCtx cast_ctx(ctx->allocator_, &dtc_params, CM_NONE, ObCharset::get_system_collation());
+            if (OB_FAIL(ObObjCaster::to_type(ObUserDefinedSQLType, cast_ctx, result, result))) {
+              LOG_WARN("failed to_type", K(ret), K(result));
+            }
+          }
           if (OB_SUCC(ret)
               && result_type.get_extend_type() > 0
               && result_type.get_extend_type() < T_EXT_SQL_ARRAY
diff --git a/src/sql/optimizer/ob_join_order.cpp b/src/sql/optimizer/ob_join_order.cpp
index 748eec4d4c..4e75fd080f 100644
--- a/src/sql/optimizer/ob_join_order.cpp
+++ b/src/sql/optimizer/ob_join_order.cpp
@@ -3684,7 +3684,8 @@ int ObJoinOrder::generate_const_predicates_from_view(const ObDMLStmt *stmt,
     if (OB_ISNULL(sel_expr = child_stmt->get_select_item(idx).expr_)) {
       ret = OB_ERR_UNEXPECTED;
       LOG_WARN("get unexpected expr", K(ret), K(idx), K(sel_expr));
-    } else if (!sel_expr->is_const_expr() || sel_expr->get_result_type().is_lob()) {
+    } else if (!sel_expr->is_const_expr() || sel_expr->get_result_type().is_lob() ||
+                ob_is_xml_sql_type(sel_expr->get_result_type().get_type(), sel_expr->get_result_type().get_subschema_id())) {
       //do nothing
     } else if (OB_FAIL(ObTransformUtils::is_expr_not_null(not_null_ctx,
                                                           sel_expr,
diff --git a/src/sql/resolver/expr/ob_shared_expr_resolver.cpp b/src/sql/resolver/expr/ob_shared_expr_resolver.cpp
index ec4fdb83d7..2bd66c2b05 100644
--- a/src/sql/resolver/expr/ob_shared_expr_resolver.cpp
+++ b/src/sql/resolver/expr/ob_shared_expr_resolver.cpp
@@ -24,6 +24,7 @@ bool ObQuestionmarkEqualCtx::compare_const(const ObConstRawExpr &left,
       (left.get_result_type().is_ext()
         && left.get_result_type().get_extend_type() > 0
         && left.get_result_type().get_extend_type() < T_EXT_SQL_ARRAY) ||
+      left.get_result_type().is_user_defined_sql_type() ||
       OB_SUCCESS != err_code_) {
     // do nothing
   } else if (left.get_expr_type() != T_QUESTIONMARK) {