让我说,我有一个查询,这个查询将在数百万个记录上进行。现在,我在何方条款中有这样的查询,
WHERE Status IN (SELECT VALUE FROM SPLIT(@Status, , ))
显然,SELECT SELIT (@status,,, ) 将在每一行操作。 我需要改进这一点 。
您既可以当前的解决方案,也可以将其性能与 INNER JOIN 作比较:
SELECT A.*
FROM YourTable A
INNER JOIN SPLIT(@Status, , ) B
ON A.Status = B.Value
如何将 SPLIT 函数的结果放置在 可变/可变/可变表格 中, 然后再对此做 INNER JOIN ?
解包您在临时表格上的字符串,然后在查询中使用该字符串。在临时表格的字段上有一个索引应该有所帮助。
create table #Split (Value varchar(10) primary key)
insert into #Split(Value)
select distinct Value
from SPLIT(@Status, , )
select SomeCol
from YourTable
where Status in (select Value from #Split)
drop table #Split
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