order by newid() 各种数据库随机查询的方法

SQL Server：

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：

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)

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：

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：

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