mysql-如何连接字符串并转换为日期字符串? [英] mysql - How to concatenate strings and convert to date the strings?

问题描述

CREATE DEFINER=`ninjaboy`@`%` PROCEDURE `getMonthlyTotalScore`(IN ninjaId int,  IN month int, IN year int)
BEGIN
    DECLARE startDate DATE;
    DECLARE endDate DATE;
    DECLARE maxDay INTEGER;

    SELECT DAY(LAST_DAY(year + '-' + month + '-01')) INTO maxDay;

    SET startDate = year + '-' + month + '-01';
    SET endDate = year + '-' + month + '-' + maxDay;

    SELECT SUM(SCORE) FROM NINJA_ACTIVITY WHERE NINJA_ID = ninjaId AND DATE BETWEEN startDate AND endDate ORDER BY DATE;
END

测试数据:

NINJA_ACTIVITY_ID | NINJA_ID | SCORE | DATE
1                   1          24      2012-05-01
2                   1          36      2012-05-06
3                   1          29      2012-05-11

函数调用:call getTotalMonthlyScore (1, 5, 2012)

我正在尝试根据ninjaId获得任何忍者的月度得分.

I'm trying to get the monthly score of any ninja based on the ninjaId.

为什么不起作用?知道我哪里出问题了吗?

Why is not working? Any idea where I am getting wrong?

推荐答案

CONCAT()是关键.

mysql> CREATE  PROCEDURE `getMonthlyTotalScore`(IN ninjaId int,  IN month int, IN year int)
        -> BEGIN
        ->     DECLARE startDate DATE;
        ->     DECLARE endDate DATE;
        ->     DECLARE maxDay INTEGER;
        -> 
        ->     SELECT year + '-' + month + '-01'; #NOTE THIS
        -> 
        ->     
        -> END;    
        -> |
    Query OK, 0 rows affected (0.00 sec)

    mysql> call getMonthlyTotalScore(1,5,2012);
        -> |
    +----------------------------+
    | year + '-' + month + '-01' |
    +----------------------------+
    |                       2016 |
    +----------------------------+
    1 row in set (0.00 sec)

之后:

mysql> CREATE  PROCEDURE `getMonthlyTotalScore`(IN ninjaId int,  IN month int, IN year int)
    -> BEGIN
    ->     DECLARE startDate DATE;
    ->     DECLARE endDate DATE;
    ->     DECLARE maxDay INTEGER;
    -> 
    ->     SELECT CONCAT(year,'-',month,'-01'); # NOTE THIS
    -> 
    ->     
    -> END;    |
Query OK, 0 rows affected (0.00 sec)

mysql> call getMonthlyTotalScore(1,5,2012);
    -> |
+------------------------------+
| CONCAT(year,'-',month,'-01') |
+------------------------------+
| 2012-5-01                    |
+------------------------------+
1 row in set (0.00 sec)

Query OK, 0 rows affected (0.00 sec)

这篇关于mysql-如何连接字符串并转换为日期字符串?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！