html - 在mysql中获取总数和组数

Question

Fiddle example

我很好奇是否有其他选项可以在一个查询中获取总计数和组计数。

使用子查询是获取此结果的首选方式:

TOTAL   OPTIONS OPTION_COUNT
4       A       3
4       B       1

表架构:

CREATE TABLE poll
    (`poll_id` int,`user_id` int,`options` varchar(30))
;

INSERT INTO poll
    (`poll_id`,`user_id`,`options`)
VALUES
    (1,1,'A'),
    (2,2,'A'),
    (3,3,'B'),
    (4,4,'A')
;

查询:

SELECT (SELECT Count(*) AS total FROM poll)AS total
,options,option_count
FROM 
(
  SELECT options,Count(options) AS option_count
  FROM poll
  GROUP BY options
)p
GROUP BY options

Answer 1

有一种方法可以使用 group by rollup

http://dev.mysql.com/doc/refman/5.0/en/group-by-modifiers.html

SELECT options,Count(options) AS option_count
FROM poll
GROUP BY options
WITH ROLLUP