Question

我有一个包含重复表达式的查询。可以写得更紧凑吗？

select id from `vacature_saved_searches`
       where `saved_search_interval` = 1 and 
              DAYOFWEEK(CURDATE()) BETWEEN 2 AND 6 and 
              `last_processing_started_datetime` < CURDATE() - INTERVAL 1 HOUR
UNION
select id from `vacature_saved_searches` 
       where `saved_search_interval` = 2 and 
              DAYOFWEEK(CURDATE()) IN (2, 4, 6) and 
             `last_processing_started_datetime` < CURDATE() - INTERVAL 1 HOUR
UNION
select id from `vacature_saved_searches` 
       where `saved_search_interval` = 3 and 
              DAYOFWEEK(CURDATE()) = 3 AND 
              `last_processing_started_datetime` < CURDATE() - INTERVAL 1 HOUR
UNION
select id from `vacature_saved_searches` 
       where `saved_search_interval` = 4 and 
              DAYOFWEEK(CURDATE()) = 3 and 
              DAYOFMONTH(CURDATE()) BETWEEN 1 AND 7 and 
              `last_processing_started_datetime` < CURDATE() - INTERVAL 1 HOUR;

Answer 1

没那么好。此外，对于这个确切的查询结果应该是相同的，但如果4个查询之间存在重叠，您将在原始UNION中获得重复。

select id 
from `vacature_saved_searches` 
where `last_processing_started_datetime` < CURDATE() - INTERVAL 1 HOUR AND
    ((`saved_search_interval` = 1 and DAYOFWEEK(CURDATE()) BETWEEN 2 AND 6) OR
     (`saved_search_interval` = 2 and DAYOFWEEK(CURDATE()) IN (2, 4, 6)) OR
     (`saved_search_interval` = 3 and DAYOFWEEK(CURDATE()) = 3) OR
     (`saved_search_interval` = 4 and DAYOFWEEK(CURDATE()) = 3 and DAYOFMONTH(CURDATE()) BETWEEN 1 AND 7))

Answer 2

不确定。为什么联合它的同一张桌子？

为什么不

select id from `vacature_saved_searches`
  where 
((`saved_search_interval` = 1 and 
              DAYOFWEEK(CURDATE()) BETWEEN 2 AND 6) 
or
(`saved_search_interval` = 2 and 
              DAYOFWEEK(CURDATE()) IN (2, 4, 6))
or 
(`saved_search_interval` = 3 and 
              DAYOFWEEK(CURDATE()) = 3)
or
(`saved_search_interval` = 4 and 
              DAYOFWEEK(CURDATE()) = 3 and 
              DAYOFMONTH(CURDATE()) BETWEEN 1 AND 7))
and `last_processing_started_datetime` < CURDATE() - INTERVAL 1 HOUR;

Answer 3

您可以结合使用DISTINCT和重新构造查询来使用OR子句而不是联合：

select DISTINCT id from `vacature_saved_searches`
   where ((`saved_search_interval` = 1 and DAYOFWEEK(CURDATE()) BETWEEN 2 AND 6) OR
         (`saved_search_interval` = 2 and DAYOFWEEK(CURDATE()) IN (2, 4, 6)) OR 
         (`saved_search_interval` = 3 and DAYOFWEEK(CURDATE()) = 3) OR 
         (`saved_search_interval` = 4 and DAYOFWEEK(CURDATE()) = 3 and 
             DAYOFMONTH(CURDATE()) BETWEEN 1 AND 7))
         AND `last_processing_started_datetime` < CURDATE() - INTERVAL 1 HOUR;

删除此MYSQL联合查询的重复

3 个答案: