support json type

src/sql/engine/expr/ob_expr_json_merge.h

@@ -0,0 +1,37 @@
+/**
+ * Copyright (c) 2021 OceanBase
+ * OceanBase CE is licensed under Mulan PubL v2.
+ * You can use this software according to the terms and conditions of the Mulan PubL v2.
+ * You may obtain a copy of Mulan PubL v2 at:
+ *          http://license.coscl.org.cn/MulanPubL-2.0
+ * THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
+ * EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
+ * MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
+ * See the Mulan PubL v2 for more details.
+ */
+
+// This file is for define of func json_merge
+#ifndef OCEANBASE_SQL_OB_EXPR_JSON_MERGE_H_
+#define OCEANBASE_SQL_OB_EXPR_JSON_MERGE_H_
+
+#include "sql/engine/expr/ob_expr_operator.h"
+#include "sql/engine/expr/ob_expr_json_merge_preserve.h"
+
+using namespace oceanbase::common;
+
+namespace oceanbase
+{
+namespace sql
+{
+class ObExprJsonMerge : public ObExprJsonMergePreserve
+{
+public:
+  explicit ObExprJsonMerge(common::ObIAllocator &alloc);
+  virtual ~ObExprJsonMerge();
+private:
+    DISALLOW_COPY_AND_ASSIGN(ObExprJsonMerge);
+};
+
+} // sql
+} // oceanbase
+#endif // OCEANBASE_SQL_OB_EXPR_JSON_MERGE_H_