Question

帮我优化下面的sql，运行很多个小时数据库：sybase

select
    too.toID,too.toName,frm.fromID,frm.fromName<br>
from
    entityClientTempTable frm, entityClientTempTable too
where
    frm.fromServerId = too.toServerId 
and
    frm.fromID < too.toID 
and 
    lower(substring(frm.fromName, 0, CHARINDEX(''------'',frm.fromName))) like lower(too.toName))

entityClientTempTable中的记录数：约五十万 entityClientTempTable表上没有索引 entityClientTempTable是一个临时表。

Answer 1

请你试试这个：

select too.toID,too.toName,frm.fromID,frm.fromName
from entityClientTempTable frm
inner join entityClientTempTable too on frm.fromServerId = too.toServerId 
       and frm.fromID < too.toID
where lower(substring(frm.fromName, 0, CHARINDEX(''------'',frm.fromName))) like lower(too.toName))

SQL查询运行很长时间

1 个答案: