mysql 选择计数与另一个选择计数

Posted 2023-02-24

【中文标题】mysql 选择计数与另一个选择计数

【英文标题】：mysql select count with another select count

【发布时间】：2012-03-05 15:03:24

【问题描述】：

如何在 mysql 中组合这两个查询？

 select count(*) as entry_count from tbl_entries where user_id = x

和

select username, avatar from tbl_users where user_id = x

我想要一个结合这 2 个查询的结果的结果。请帮帮我！

谢谢！

【参考方案1】：

select username, 
       avatar,
       (select count(*) from tbl_entries where user_id = x) as entry_count
from tbl_users 
where user_id = x

【参考方案2】：

select username,
       avatar,
       (select count(*) from tbl_entries where user_id = x) AS cnt
  from tbl_users
 where user_id = x

【参考方案3】：

试试这个：

SELECT a.username,
        a.avatar,
        COUNT(*) as entry_count,
FROM tbl_Users a LEFT JOIN tbl_entries b ON
        a.user_ID = b.user_ID
WHERE a.user_ID = x
GROUP BY a.username

【参考方案4】：

试试这个：

SELECT U.username, U.avatar, 
    count(*) AS entry_count 
FROM tbl_users AS U
LEFT JOIN tbl_entries AS E ON U.user_id = E.user_id
WHERE user_id = x
GROUP BY U.user_id;

【参考方案5】：

选择用户名， 头像， (select count(*) from tbl_entries where user_id = U.user_id) AS cnt FROM tbl_users AS U WHERE user_id = x