Question

我的表结构如下（带数据）：

+------------------------------------+
|id    fname     category  city      |
|1     ram       cook      kathmandu |
|2     shyam     cook      lalitpur  |
|3     krishna   maid      patan     |
|4     jay       maid      kupondole |
|5     rajan     maid      ratnapark |
+------------------------------------+

查询应该使用随机烹饪和女佣一次返回2行（cook和maid）。我怎么能这样做？

Answer 1

两种选择：

(SELECT * FROM TableName WHERE category='cook' ORDER BY rand() limit 1)
UNION ALL
(SELECT * FROM TableName WHERE category='maid' ORDER BY rand() limit 1)

请参阅SQL Fiddle中的结果。

或

SELECT * FROM TableName WHERE category IN ('cook','maid') GROUP BY category ORDER BY rand() limit 2

请参阅SQL Fiddle中的结果。

结果：

ID FNAME CATEGORY CITY 1 ram cook kathmandu 5 rajan maid ratnapark

Answer 2

select fname
from table
where category="cook"
order by RAND()
LIMIT 1
UNION
select fname
from table
where category="maid"
order by RAND()
LIMIT 1

Answer 3

子查询负责查找随机ID

SELECT *
FROM mytable
WHERE id IN
    (SELECT round(rand()*(max(id)-min(id)+1))+min(id)
     FROM mytable
     GROUP BY category);

如何选择2个随机类别数据

3 个答案: