mysql - MYSQL where 子句中的条件

Question

我有一个查询，如果名为 OrderBy 的标志为 1，则它是一个日历事件，我需要检查两个日期时间字段之间的范围。而所有其他类型，我们只检查您查看的日期。我研究了 if 语句并看到许多建议使用 case 的帖子，所以我尝试将它实现到我的查询中。我的查询需要 where 中的条件。我知道我有语法问题，这就是我来这里的原因，希望有人能指出正确的方法来做到这一点。

谢谢你的时间

我目前的查询

SELECT          activities.*, 
                activitytypes.orderby 
FROM            activities 
LEFT OUTER JOIN activitytypes 
ON              activities.typeid = activitytypes.typeid 
WHERE           activities.userid = 86 
AND             activities.typeid NOT IN ( 5, 
                                          10, 
                                          11, 
                                          12, 
                                          19 ) 
AND 
                CASE 
                                WHEN activities.orderby = 1 THEN activities.starttime >= '2013-08-26 04:00:00' 
                                AND             activities.endtime <= '2013-08-27 04:00:00' 
                                ELSE activities.activitydate = '2013-08-26' 
                                order BY        activitytypes.orderby, 
                                                activities.starttime

Answer 1

只要使用足够的括号，您就可以使用 AND 和 OR 来执行此操作。

我还假设 activities.OrderBy 可以为空。如果不是这种情况，您可以删除空检查:

SELECT activities.*, 
       activitytypes.orderby 
FROM   activities 
       LEFT OUTER JOIN activitytypes 
                    ON activities.typeid = activitytypes.typeid 
WHERE  activities.userid = 86 
       AND activities.typeid NOT IN ( 5, 10, 11, 12, 19 ) 
       AND ( ( activities.orderby = 1 
               AND activities.starttime >= '2013-08-26 04:00:00' 
               AND activities.endtime <= '2013-08-27 04:00:00' ) 
              OR ( ( activities.orderby IS NULL 
                      OR activities.orderby != 1 ) 
                   AND activities.activitydate = '2013-08-26' ) ) 
ORDER  BY activitytypes.orderby, 
          activities.starttime 

或者，如果您仍想使用 CASE，您只需使用 END 关闭您的 CASE 语句，如下所示:

SELECT          activities.*, 
                activitytypes.orderby 
FROM            activities 
LEFT OUTER JOIN activitytypes 
ON              activities.typeid = activitytypes.typeid 
WHERE           activities.userid = 86 
AND             activities.typeid NOT IN ( 5, 10, 11, 12, 19 ) 
AND             ( 
                  CASE 
                  WHEN activities.orderby = 1 THEN
                    activities.starttime >= '2013-08-26 04:00:00' AND activities.endtime <= '2013-08-27 04:00:00'
                  ELSE
                    activities.activitydate = '2013-08-26' 
                  END
                ) 
ORDER BY        activitytypes.orderby, 
                activities.starttime