Question

我尝试在两个相同的表上使用count（）来获得某种关系这是我的查询

SELECT b.id, count(a) count(b.id) from 
checkins_small a, checkins_small b 
WHERE a.id =22 AND a.city = b.city AND a.date = b.date GROUP BY b.id ;

这是基于签到数据，我想找到所有在同一城市和同一日期登记的用户22所做的人。但是这个查询总是给我一个masive数字。 count（a.id）和count（b.id）的结果总是一样的如何解决这个问题？

SELECT a.id, count(a.id) from checkins_small a group by a.id order by count(a.id) DESC LIMIT 10;

此查询将给出以下结果：

userid  checkin times
22     ;  1783
267    ;  1607
177    ;  1508
130    ;  1477
205    ;  1456
2      ;  1368
323    ;  1151
111    ;  1092
337    ;  940
53     ;  896

现在，我想找到所有与用户22在同一个日期和同一城市办理登机手续的人以及这些人签到的时间。所以结果将是这样的

   user_id   times

Answer 1

SELECT
   COUNT(b.ID) as CT,
   b.date
FROM
   checkins_small a
   INNER JOIN
   checkins_small b on b.city = a.city and b.date = a.date
WHERE
   a.ID = 22
GROUP BY
   b.date

Answer 2

SELECT b.id AS user_id,
   COUNT(b.id) AS times
FROM   (SELECT DISTINCT
           id,
           city,
           date
    FROM   checkins_small
    WHERE  id = 22) a,
   checkins_small b
WHERE  a.city = b.city
   AND a.date = b.date
   AND a.id <> b.id
GROUP  BY b.id;

如何指望两个相同的表

2 个答案: