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src/sql/engine/expr/ob_expr_greatest.h

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+/**
+ * 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.
+ */
+
+#ifndef _OB_SQL_EXPR_GREATEST_H_
+#define _OB_SQL_EXPR_GREATEST_H_
+
+#include "sql/engine/expr/ob_expr_operator.h"
+#include "sql/engine/expr/ob_expr_least.h"
+
+namespace oceanbase {
+namespace sql {
+class ObExprBaseGreatest : public ObExprBaseLeastGreatest {
+  public:
+  explicit ObExprBaseGreatest(common::ObIAllocator& alloc, int32_t param_num,
+      ObExprOperatorType type = T_FUN_SYS_GREATEST, const char* name = N_GREATEST);
+  virtual ~ObExprBaseGreatest();
+  virtual int calc_result_typeN(
+      ObExprResType& type, ObExprResType* types_stack, int64_t param_num, common::ObExprTypeCtx& type_ctx) const;
+  virtual int calc_resultN(
+      common::ObObj& result, const common::ObObj* objs_stack, int64_t param_num, common::ObExprCtx& expr_ctx) const;
+  static int calc(common::ObObj& result, const common::ObObj* objs_stack, int64_t param_num,
+      const ObExprResType& expected_type, common::ObExprCtx& expr_ctx);
+  virtual int cg_expr(ObExprCGCtx& op_cg_ctx, const ObRawExpr& raw_expr, ObExpr& rt_expr) const override;
+  static int calc_greatest(const ObExpr& expr, ObEvalCtx& ctx, ObDatum& expr_datum);
+
+  private:
+  // disallow copy
+  DISALLOW_COPY_AND_ASSIGN(ObExprBaseGreatest);
+};
+
+class ObExprGreatestMySQL : public ObExprBaseGreatest {
+  public:
+  explicit ObExprGreatestMySQL(common::ObIAllocator& alloc);
+  virtual ~ObExprGreatestMySQL();
+  virtual int calc_result_typeN(
+      ObExprResType& type, ObExprResType* types_stack, int64_t param_num, common::ObExprTypeCtx& type_ctx) const;
+
+  private:
+  DISALLOW_COPY_AND_ASSIGN(ObExprGreatestMySQL);
+};
+
+class ObExprGreatestMySQLInner : public ObExprBaseGreatest {
+  public:
+  explicit ObExprGreatestMySQLInner(common::ObIAllocator& alloc);
+  virtual ~ObExprGreatestMySQLInner();
+  virtual int calc_result_typeN(
+      ObExprResType& type, ObExprResType* types_stack, int64_t param_num, common::ObExprTypeCtx& type_ctx) const;
+
+  private:
+  DISALLOW_COPY_AND_ASSIGN(ObExprGreatestMySQLInner);
+};
+
+class ObExprOracleGreatest : public ObExprBaseGreatest {
+  public:
+  explicit ObExprOracleGreatest(common::ObIAllocator& alloc);
+  virtual ~ObExprOracleGreatest();
+  virtual int calc_result_typeN(
+      ObExprResType& type, ObExprResType* types_stack, int64_t param_num, common::ObExprTypeCtx& type_ctx) const;
+
+  private:
+  DISALLOW_COPY_AND_ASSIGN(ObExprOracleGreatest);
+};
+
+}  // namespace sql
+}  // namespace oceanbase
+#endif /* _OB_SQL_EXPR_GREATEST_H_ */