Question

这是我的查询

SELECT  a.id,
        a.venue_id, 
        a.user_id, 
        m1.profilenam AS user_profilename,
        m1.photo_thumb AS user_photo_thumb,
        m2.profilenam AS venue_profilename, 
        m2.photo_thumb AS venue_photo_thumb 
FROM announce_arrival AS a 
    INNER JOIN members AS m1 
        ON a.user_id = m1.mem_id
    INNER JOIN members AS m2 
        ON a.venue_id = m2.mem_id
GROUP BY a.venue_id, a.user_id
LIMIT 0,10 
ORDER BY date DESC,
         time DESC

我如何在此查询中使用count（*），我就像这样使用

SELECT DISTINCT COUNT(*) 
 FROM announce_arrival AS a       
 INNER JOIN members as m1 ON (a.user_id = m1.mem_id)
 INNER JOIN members as m2 ON (a.venue_id= m2.mem_id)
 GROUP BY a.venue_id, a.user_id LIMIT 0,10  ORDER BY date DESC,time DESC;

但它的表现计数（*） 7 3 1

我想要总数。

Answer 1

您可以将查询包装到select count（*）中，如下所示：

SELECT COUNT(*) FROM
  (SELECT a.id,a.venue_id, a.user_id, m1.profilenam as
    user_profilename,m1.photo_thumb AS user_photo_thumb,m2.profilenam AS
    venue_profilename, m2.photo_thumb AS venue_photo_thumb FROM announce_arrival
    AS a INNER JOIN members as m1 ON (a.user_id = m1.mem_id) INNER JOIN members
    as m2 ON (a.venue_id= m2.mem_id) GROUP BY a.venue_id, a.user_id)

Answer 2

您可以将查询包装在另一个SELECT中：

SELECT COUNT(*) AS total FROM (
SELECT DISTINCT COUNT(*) 
FROM announce_arrival AS a       
INNER JOIN members as m1 ON (a.user_id = m1.mem_id)
INNER JOIN members as m2 ON (a.venue_id= m2.mem_id)
GROUP BY a.venue_id, a.user_id LIMIT 0,10  ORDER BY date DESC,time DESC) AS t

或者如果您想要所有DISTINCT COUNT(*)的总和，请尝试：

SELECT SUM(cnt) AS total FROM (
SELECT DISTINCT COUNT(*) AS cnt
FROM announce_arrival AS a       
INNER JOIN members as m1 ON (a.user_id = m1.mem_id)
INNER JOIN members as m2 ON (a.venue_id= m2.mem_id)
GROUP BY a.venue_id, a.user_id LIMIT 0,10  ORDER BY date DESC,time DESC) AS t

Answer 3

来自docs about found_rows()：

要获取此行数，请包含a   SQL_CALC_FOUND_ROWS选项中   SELECT语句，然后调用   之后是FOUND_ROWS（）：

mysql> SELECT SQL_CALC_FOUND_ROWS * FROM tbl_name WHERE id > 100 LIMIT 10;

mysql> SELECT FOUND_ROWS();

第二个SELECT返回一个数字   表示第一行的行数   如果它已经返回SELECT   没有LIMIT条款而写的。

即，在第一个查询中SQL_CALC_FOUND_ROWS之后添加SELECT，并将第二个查询替换为SELECT FOUND_ROWS()。

Answer 4

摆脱GROUP BY，LIMIT和ORDER。如果你需要一个总计数，它们是没用的，没有意义（尤其是LIMIT）。 DISTINCT也没有意义。

SELECT COUNT(*) 
 FROM announce_arrival AS a       
 INNER JOIN members as m1 ON (a.user_id = m1.mem_id)
 INNER JOIN members as m2 ON (a.venue_id= m2.mem_id)

Answer 5

试试这个

      SELECT COUNT(a.user_id) 
      FROM announce_arrival AS a       
      INNER JOIN members as m1 ON (a.user_id = m1.mem_id)
      INNER JOIN members as m2 ON (a.venue_id= m2.mem_id)
      GROUP BY  a.user_id LIMIT 0,10;

如果您正在使用计数，则无需通过

发出命令

如何从查询中获取总计数？

5 个答案: