网上有很多人都在谈论or与in的使用,有的说二者没有什么区别,其实不然,估计是测试做的不够,其实or的效率为O(n),而in的效率为O(log2n),当基数越大时,in的效率就能凸显出来了。 有人做了这么一组实验(测试库数据为1000万条记录):A组分别用or与in查询3条记录,B组分别用or与in查询120条记录,C组分别用or...
SQL Server 2012 The fix for this issue was first released in Cumulative Update 1 for SQL Server 2012. For more information about this cumulative update package, click the following article number to view the article in the Microsoft Knowledge Base: 2679368Cumulative update package 1 for SQL Serve...
Microsoft SQL Server 2005 hotfixes are created for specific SQL Server service packs. You must apply a SQL Server 2005 Service Pack 3 hotfix to an installation of SQL Server 2005 Service Pack 3. By default, any hotfix that is provided in a SQL Server service pack is inc...
每一个insert,update,delete语 For example, given a multicolumn index on the au_lname, au_fname columns of the authors table in the pubs database, 下面这个query语句利用了au_lname上的索引 SELECT au_id, au_lname, au_fname FROM authors WHERE au_lname = ’White’ AND au_fname = ’Jo...
SQL Server Execution Times: CPU time=2044ms, elapsed time=2075ms. 小结: 从上面的结果可以看出来,获取订单总记录数、获取第一页的订单信息总时间在150毫秒左右就可以查出来,不过在根据订单号in查询订单信息的时候,发现耗时2秒。细心的园友应该也发现我在这个“统计信息”里面多复制了一些东西,有两个表的扫描...
小虫快跑 从一个错误提示引出SQL中in和or的问题。 希望大家帮忙解决下。。 环境是 SQL Server 2000 例子表 create table [table1] ( a int identity, b int ) 再一次调试SQL语句事有如下查询操作 select [a],[b] from [table1] where [aa] in (1,2,3)...
In some cases, like when customers use Object-relational Mapping tools (ORM) Like Entity framework or LINQ, part of the code at the end will be converted to...
Programming with FileStreams in SQL Server 2008 Patterns and Practices: Simplifying Patterns and Practices Usability in Practice: Useful, Usable and Desirable: Usability as a Core Development Competence The Unconference: Where Geeks JIT Together
Method 1: Use SQL Server Management Studio (SSMS) and SQL Server Configuration Manager In SSMS, openObject Explorer, right-click a server instance and selectProperties. In the left panel, select theDatabase Settingspage. InDatabase default locations, view the current default locations...
In the Backup file field, go to the location of the backup folder you created in step 1. Select OK . If you're installing the new SQL Server instance on a different machine, copy all backup files from the backup folder to the restore folder. ...