support json type

src/sql/engine/expr/ob_expr_json_object.h

@@ -0,0 +1,42 @@
+/**
+ * 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 contains declare of the json_object.
+#ifndef OCEANBASE_SQL_OB_EXPR_JSON_OBJECT_H_
+#define OCEANBASE_SQL_OB_EXPR_JSON_OBJECT_H_
+
+#include "sql/engine/expr/ob_expr_operator.h"
+
+using namespace oceanbase::common;
+
+namespace oceanbase
+{
+namespace sql
+{
+class ObExprJsonObject : public ObFuncExprOperator
+{
+public:
+  explicit ObExprJsonObject(common::ObIAllocator &alloc);
+  virtual ~ObExprJsonObject();
+  int calc_resultN(ObObj &result, const ObObj *objs, int64_t param_num, ObExprCtx &expr_ctx) const;
+  virtual int calc_result_typeN(ObExprResType& type, ObExprResType* types, int64_t param_num, 
+    common::ObExprTypeCtx& type_ctx) const override;
+  static int eval_json_object(const ObExpr &expr, ObEvalCtx &ctx, ObDatum &res);
+  virtual int cg_expr(ObExprCGCtx &expr_cg_ctx, const ObRawExpr &raw_expr, ObExpr &rt_expr) const override;
+
+private:  
+    DISALLOW_COPY_AND_ASSIGN(ObExprJsonObject);
+};
+
+} //sql
+} //oceanbase
+#endif //OCEANBASE_SQL_OB_EXPR_JSON_OBJECT_H_