[CP] fix json output type

deps/oblib/src/common/object/ob_object.h

@@ -135,11 +135,12 @@ public:
       set_collation_type(CS_TYPE_INVALID);
     } else if (ObHexStringType == type_) {
       set_collation_type(CS_TYPE_BINARY);
+    } else if (ob_is_json(static_cast<ObObjType>(type_))) {
+      set_collation_type(CS_TYPE_UTF8MB4_BIN);
     } else if (!ob_is_string_type(static_cast<ObObjType>(type_)) && 
                !ob_is_lob_locator(static_cast<ObObjType>(type_)) &&
                !ob_is_raw(static_cast<ObObjType>(type_)) && 
-               !ob_is_enum_or_set_type(static_cast<ObObjType>(type_)) && 
-               !ob_is_json(static_cast<ObObjType>(type_))) {
+               !ob_is_enum_or_set_type(static_cast<ObObjType>(type_))) {
       set_collation_level(CS_LEVEL_NUMERIC);
       set_collation_type(CS_TYPE_BINARY);
     }

src/sql/engine/aggregate/ob_aggregate_function.cpp

@@ -3285,7 +3285,6 @@ int ObAggregateFunction::get_json_arrayagg_result(const ObAggregateExpression *&
             LOG_WARN("convert string collation failed", K(ret), K(cs_type), K(origin_str.length()));
           } else {
             converted_obj.set_string(val_type, converted_str);
-            converted_obj.set_collation_type(CS_TYPE_UTF8MB4_BIN);
             cs_type = CS_TYPE_UTF8MB4_BIN;
           }
         }
@@ -3430,7 +3429,6 @@ int ObAggregateFunction::get_json_objectagg_result(const ObAggregateExpression *
                 LOG_WARN("convert string collation failed", K(ret), K(cs_type1), K(origin_str.length()));
               } else {
                 converted_obj.set_string(val_type1, converted_str);
-                converted_obj.set_collation_type(CS_TYPE_UTF8MB4_BIN);
                 cs_type1 = CS_TYPE_UTF8MB4_BIN;
               }
             }