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order by newid() 各种数据库随机查询的方法

程序员文章站 2023-12-10 09:25:22
sql server:复制代码 代码如下:select top n * from table order by newid()   view plain...

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