[FEAT MERGE]4_1_sql_feature

Co-authored-by: leslieyuchen <leslieyuchen@gmail.com>
Co-authored-by: Charles0429 <xiezhenjiang@gmail.com>
Co-authored-by: raywill <hustos@gmail.com>

src/sql/engine/expr/ob_expr_name_const.h

@@ -0,0 +1,41 @@
+// (C) Copyright 2015-2016 Alibaba Inc. All Rights Reserved.
+// This program is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License
+// version 2 as published by the Free Software Foundation.
+// Version: $Id$
+//  Authors:
+//    yebangyu <bangyu.yby@alibaba-inc.com>
+//  Normalizer:
+//    yebangyu <bangyu.yby@alipay.com>
+// This file is for declaration of func get_user_var
+
+#ifndef _OCEANBASE_SQL_OB_EXPR_NAME_CONST_H_
+#define _OCEANBASE_SQL_OB_EXPR_NAME_CONST_H_
+#include "lib/ob_name_def.h"
+#include "sql/engine/expr/ob_expr_operator.h"
+#include "sql/session/ob_sql_session_info.h"
+
+namespace oceanbase
+{
+namespace sql
+{
+class ObExprNameConst : public ObFuncExprOperator
+{
+public:
+  explicit  ObExprNameConst(common::ObIAllocator &alloc);
+  virtual ~ObExprNameConst();
+  virtual int calc_result_type2(ObExprResType &type,
+                                ObExprResType &type1,
+                                ObExprResType &type2,
+                                common::ObExprTypeCtx &type_ctx) const;
+  virtual int cg_expr(ObExprCGCtx &expr_cg_ctx, const ObRawExpr &raw_expr,
+                              ObExpr &expr) const override;
+  static int eval_name_const(const ObExpr &expr, ObEvalCtx &ctx, ObDatum &res);
+private:
+  // disallow copy
+  DISALLOW_COPY_AND_ASSIGN(ObExprNameConst);
+};
+
+} //sql
+} //oceanbase
+#endif //_OCEANBASE_SQL_OB_EXPR_NAME_CONST_H_