Question

如何获得每个用户贡献/出现在该特定类别的数量。下表有用户，类别。我正在寻找所有用户已经贡献/出现在下表中并对其进行排名的锄头计数。

CREATE TABLE if not exists tblA
(
id int(11) NOT NULL auto_increment ,
user varchar(255),
 category int(255),
 PRIMARY KEY (id)
);


INSERT INTO tblA (user, category ) VALUES
('1', '1'),
('1', '2'),
('1', '3'),
('1', '1'),
('2', '1'),
('2', '1');

响应如下：搜索其＆＃39; 1＆＃39;

的类别

user  category    count    rank

1       1         2        1
2       1         2        2

Answer 1

SELECT USER,
       category,
       count(*) AS num
FROM tblA
WHERE category=1
GROUP BY USER,
         category
ORDER BY num DESC;

演示：http://sqlfiddle.com/#!2/d4458/10/0

Answer 2

SET @prev_value = NULL;
SET @rank_count = 0;
SELECT
  i.*,
  CASE 
    WHEN @prev_value = i.num THEN @rank_count
    ELSE @rank_count := @rank_count + 1
  END AS rank
FROM (
  SELECT 
    user,category,COUNT(*) AS num
  FROM tblA
  WHERE category=1 
  GROUP BY user,category 
  ORDER BY num DESC
) i;

获取特定类别的所有用户的数量并对其进行排名

2 个答案: