如何声明一个datetime变量?

My code:

我的代码:

DECLARE report_date DATETIME;
set report_date='2013-01-17 00:00:00';

SELECT  *
  FROM `NMPP`.`capacitypersecond` 
  WHERE `StreamDT` >=report_date and `StreamDT` < '2013-01-18 00:00:00'  ;

SELECT  *
  FROM `NMPP`.`capacityperHr` 
  WHERE `StreamDT` >=report_date and `StreamDT` < '2013-01-18 00:00:00'  ;

SELECT  *
  FROM `NMPP`.`capacityperDay` 
  WHERE `TJLDate` >=report_date and `TJLDate` < '2013-01-18 00:00:00'  ;

- - - - - -

DECLARE report_date DATETIME;
/* SQL Error (1064): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'DECLARE report_date DATETIME' at line 1 */
/* Affected rows: 0  Found rows: 0  Warnings: 0  Duration for 0 of 5 queries: 0.000 sec. */

3 个解决方案

#1

get rid of declare:

摆脱声明:

set @report_date = '2013-01-17 00:00:00';

SELECT  *
  FROM `NMPP`.`capacitypersecond` 
  WHERE `StreamDT` >= @report_date and `StreamDT` < '2013-01-18 00:00:00'  ;

#2

or with cast:

或与演员:

set @report_date = cast('2013-01-17 00:00:00' as datetime);

#3

-1

All the DECLARE should be at the start of the trigger,stored procedure.

所有的声明应该在触发器的开始，存储过程。

This is not a C++ like language where you can mix declarations and statements, but more like C, where all declarations must be done before all statements.

这不是一个c++语言，您可以将声明和语句混合在一起，但更像C，在所有语句之前都必须执行所有声明。

#1