Question

我想从表中检索随机行，但这些行必须按类别排序。

select category, 
   (select order_number 
   from orders 
   where order_number in (123,125,128,129,256,263,966,258,264,159,786) 
   order by rand()) 
from orders 
order by category

这是我试过的查询。但是，它会检索表中的整个数据。

工作查询;

SELECT category,order_number FROM (
    SELECT category,order_number 
    from orders 
    where order_number in (`$order_numbers_variable`) 
    order by rand()
) order by category

Answer 1

我认为要求是： 从“类别”排序的表格中检索“N”个随机行。

假设 N 10 。如果要更改行数，请在LIMIT子句中更改它。

SELECT * FROM (
    SELECT category from orders ORDER BY rand() ASC  LIMIT 10
) AS innerResult 
ORDER BY innerResult.category

MySQL选择order by的随机行

1 个答案: