sql文章实在是很多,说实在的,我也曾经到处找这样的文章,什么不要使用sql数据库打交道的程序员的必修课,所以写了此文,与朋友们共勉。
文章,这个网上资料比较多了。@H_403_22@
sqlsqlsql查询。@H_403_22@
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T_UserInfo
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Userid varchar20UserName varchar20@H_403_22@
RegTimeTel varchar20@H_403_22@
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1
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T_UserInfo
@IVARCHAR20VARCHAR20@H_403_22@
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@I@I1
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sql@H_403_22@
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INDEX_UseridT_UserInfoUserid@H_403_22@
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INDEX_UseridT_UserInfoUserid@H_403_22@
删除索引@H_403_22@
T_UserInfoINDEX_Userid
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显示有关由sql生成的磁盘活动量的信息@H_403_22@
IO@H_403_22@
关闭有关由sql生成的磁盘活动量的信息@H_403_22@
IO@H_403_22@
显示@H_403_22@
关闭@H_403_22@
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IO@H_403_22@
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查询语句:@H_403_22@
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sql
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显示如下:@H_403_22@
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次数@H_403_22@
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查询而放入缓存的页数@H_403_22@
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查询有多种写法,那么这四个值中的逻辑读
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显示:@H_403_22@
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查询时,逻辑读就是要读两页@H_403_22@
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查询语句,然后再L@H_403_22@
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,
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查询计划和如何查看对
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sqlL@H_403_22@
IO功能的不同sql@H_403_22@
查询速度越快@H_403_22@
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sqlsqlsql@H_403_22@
INDEXT_UserInfo.INDEX_Userid
显示语句执行情况的详细信息
*FROMT_UserInfoWHEREUSERIDLIKE@H_403_22@
cpu@H_403_22@
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*FROMT_UserInfoWHEREUSERIDLIKE@H_403_22@
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加上索引:@H_403_22@
关闭:@H_403_22@
CLUSTEREDINDEXINDEX_UseridT_UserInfo(Userid@H_403_22@
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*FROMT_UserInfoWHEREUSERIDLIKE@H_403_22@
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*FROMT_UserInfoWHEREUSERIDLIKE@H_403_22@
= 'ABCDE8' AND [T_UserInfo].[Userid] < 'ABCDE9'),WHERE:(like([T_UserInfo].[Userid],NULL)) ORDERED FORWARD)Ctrl+L@H_403_22@
+L@H_403_22@
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*FROMT_UserInfoWHERELEFT(USERID,4@H_403_22@
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*FROMT_UserInfoWHERELEFT(USERID,4@H_403_22@
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[图形界面也有对cpu和IO的消耗,也可以看出来哪个最优!]@H_403_22@
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@H_403_22@sqlsql文章真的是那样吗?你自己试试就知道了,而不必盲目去记那些东西,自己试试,看看sql@H_403_22@
sqlsql查询sql函数用不用索引?查询呢?在这里我不一一去试给大家看了,只要知道了如何去看sql@H_403_22@
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查询功能的sqlsql查询计划、通过其优化后而执行的sqlsql@H_403_22@
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sql查询写法语句的执行计划,这一点在非聚集索引上特别明显,还有就是在多cpucpu用户并发情况下,同一写法的查询语句执行计划会有所不同,这个就需要大家有机会去试验了分享@H_403_22@
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原文链接:https://www.f2er.com/mssql/64149.html