order by newid() 各种数据库随机查询的方法

所属分类：数据库 / MsSql 阅读数： 1325

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SQL Server：

复制代码代码如下:

Select TOP N * From TABLE Order By NewID()
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Select TOP N * From TABLE Order By NewID()

Select TOP N * From TABLE Order By NewID()

NewID()函数将创建一个 uniqueidentifier 类型的唯一值。上面的语句实现效果是从Table中随机读取N条记录。

Access：

复制代码代码如下:

Select TOP N * From TABLE Order By Rnd(ID)
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Select TOP N * From TABLE Order By Rnd(ID)

Select TOP N * From TABLE Order By Rnd(ID)

Rnd(ID) 其中的ID是自动编号字段，可以利用其他任何数值来完成，比如用姓名字段(UserName)

复制代码代码如下:

Select TOP N * From TABLE Order BY Rnd(Len(UserName))
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Select TOP N * From TABLE Order BY Rnd(Len(UserName))

Select TOP N * From TABLE Order BY Rnd(Len(UserName))

MySql：

复制代码代码如下:

Select * From TABLE Order By Rand() Limit 10
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Select * From TABLE Order By Rand() Limit 10

Select * From TABLE Order By Rand() Limit 10

postgreSQL：

复制代码代码如下:

select * from glxt022 order by random() limit 5   
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select * from glxt022 order by random() limit 5

SQL SERVER的优化建议与方法