Question

我有2个表，我需要在一个查询中选择和计算行，也许有人可以帮助我，我的查询是：

SELECT
    c.id, c.first_name, c.last_name, c.speciality, c.level, c.email, c.skype, c.city, 
    s.status_type, c.status_id, c.linkedin, c.link_cv, c.interview_res, c.createdAt,
    c.updatedAt, c.recruiter_id, u.first_name AS fname, u.last_name AS lname
FROM
    Candidates c
    JOIN Users u 
        ON c.recruiter_id = u.id
    JOIN Statuses s
        ON s.id = c.status_id
WHERE
    c.deleted = false

我需要计算响应我的选择并计算它们的行数。

示例输出（我想要的）：

count | fname  | lname  | ..... |
---------------------------------
3     | Ihor   | Shmidt | ...   |
3     | Andre  | Agassi | ....  |
3     | Roger  | Federer| ..... |

即。我希望我选择的字段和计数

Answer 1

在查询的“from”部分之前，请添加count（*）。它将为您提供行数。

Select ......, count (*) from Candidates c 
JOIN Users u ON c.recruiter_id = u.id 
JOIN Statuses s on s.id = c.status_id
WHERE c.deleted = false;

Answer 2

COUNT（*）作为计数或COUNT（c.id）作为计数

SELECT COUNT(*) as count,c.id, c.first_name, c.last_name, c.speciality, c.level, c.email,
    c.skype, c.city, s.status_type, c.status_id, c.linkedin, c.link_cv, c.interview_res,
    c.createdAt, c.updatedAt, c.recruiter_id, u.first_name AS fname, u.last_name AS lname 
  FROM Candidates c 
  JOIN Users u
    ON c.recruiter_id = u.id
  JOIN Statuses s
    ON s.id = c.status_id
  WHERE c.deleted = false;

Answer 3

SELECT c.id, ( SELECT COUNT(*) FROM Candidates c 
JOIN Users u ON c.recruiter_id = u.id 
JOIN Statuses s ON s.id = c.status_id 
WHERE c.deleted = false ) AS count  FROM Candidates 
c JOIN Users u ON c.recruiter_id = u.id 
JOIN Statuses s ON s.id = c.status_id 
WHERE c.deleted = false ;

选择并计算行数

3 个答案: