Question

我希望我的查询显示获得的结果总数。

例如，如果我执行此查询：

SELECT user, email FROM users WHERE user = 'Daniel';

显示第三列以及总行数。使用user = 'Daniel'，我总共有13条记录，这就是我要显示的记录：

user          email                total
-------------------------------------------------
Daniel        email1@gmail.com     13
Daniel        email2@gmail.com     13
Daniel        email3@gmail.com     13
Daniel        email4@gmail.com     13
....

可以这样做吗？

Answer 1

尝试如下

 SELECT u2.user, u2.email,
(select count(*) from users u1 where u1.user=u2.user ) as total
  FROM users u2
 WHERE u2.user = 'Daniel';

如果mysql版本> = 8.0，则可以使用count（）窗口函数

select user,email,count(*) over()  as total
from  users
     WHERE user = 'Daniel'

Answer 2

我更喜欢在这里使用解析函数：

SELECT
    user,
    email,
    COUNT(*) OVER () total
FROM users
WHERE user = 'Daniel';

如果由于使用的是MySQL的早期版本而无法使用解析函数，请使用联接：

SELECT
    u1.user,
    u1.email,
    u2.cnt AS total
FROM users u1
INNER JOIN
(
    SELECT user, COUNT(*) AS cnt
    FROM users
    -- we could also restrict to Daniel here, but I am showing a general
    -- solution for multiple users
    GROUP BY user
) u2
    ON u1.user = u2.user
WHERE
    u1.user = 'Daniel';

Answer 3

我不明白为什么您需要为组中的所有行重复相同的计数。不过，以下查询会执行您想要的相同操作

    Select user, email, count(distinct *) 
       over
     () as total from table ;

获取查询的行数

3 个答案: