select * from gmvcsbase.base_file file,gmvcsbase.base_user user,gmvcsbase.base_department dep,gmvcsbase.base_workstation work
where file.police_id=user.police_id and user.dep_code=dep.code and file.workstation_sid=work.sid and file.capture_time>='2013-10-30'
AND file.capture_time<='2014-03-19 23:59:59' ORDER BY file.id DESC LIMIT 0,20
select * from gmvcsbase.base_file file,gmvcsbase.base_user user,gmvcsbase.base_department dep, gmvcsbase.base_workstation work,
(
select file.id
from gmvcsbase.base_file file,gmvcsbase.base_user user,gmvcsbase.base_department dep, gmvcsbase.base_workstation work
where file.police_id=user.police_id and user.dep_code=dep.code and file.workstation_sid=work.sid and file.capture_time>='2013-11-30'
AND file.capture_time<='2014-03-19 23:59:59'
ORDER BY file.import_time DESC LIMIT 0,20
) as t
where file.police_id=user.police_id and user.dep_code=dep.code and file.workstation_sid=work.sid and file.id=
ORDER BY file.import_time DESC
关于优化sql查询的一个方法。
原创wx5eba5c8cb0b6f ©著作权
文章标签 sql 数据库查询 文章分类 SQL Server 数据库

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优化一个小时不出结果的SQL
今天刚清闲点,在网上看些资料,这时,用户QQ上发来求助,说一个更新数据的SQL语句很慢,都一个小时了也不出结果,于是,了解下具体
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关于SQL Server镜像的一个小误区
关于SQL Server镜像的一个小误区
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