在一個查詢中按不同條件選擇幾條隨機行

Question

我想從level = 1的表中選擇4個隨機行，並從level = 2的同一個表中選擇4個隨機行。我如何在1個查詢中做到這一點？

Answer 1

select * from (select * from your_table 
       where level = 1 order by rand() limit 4) x 
union all 
select * from (select * from your_table 
       where level = 2 order by rand() limit 4) y 

Answer 2

嘗試像這樣...

SELECT product_id, title, description FROM products WHERE active = 1 AND stock > 0 ORDER BY RAND() LIMIT 4;