试图将计数函数添加到一个复杂的查询PHP MYSQL

Question

我有一个复杂的查询组成的大量的内部和左连接，我试图使用SQL的COUNT函数返回某个表中的记录数。

我正在尝试使用proposal_id获取每个提案的'held_proposals'表中的记录数，因为我将使用foreach循环将数据输出到表中。

从本质上讲，我想说明有多少学生对每个提案“举行”提案。

这是我的尝试：

SELECT p.proposal_id, p.proposal_title, p.description, u.user_record_id, u.forename, u.surname, c.course_title, h.*, 
GROUP_CONCAT(DISTINCT t.tag_title) AS tags FROM proposal p 

     LEFT JOIN user u on u.user_record_id = p.user_record_id 

     LEFT JOIN course_details c on c.course_code = p.course_code 

     LEFT JOIN record r on r.proposal_id = p.proposal_id 

     LEFT JOIN proposal_tags pt on pt.proposal_id = p.proposal_id 

     LEFT JOIN tag_details t on t.tag_code = pt.tag_code 

LEFT JOIN (
      SELECT h.student_record_id, COUNT(*) AS Held 
      FROM held_proposals h 
     ) H on h.proposal_id = p.proposal_id 
     WHERE p.source = "Supervisor" 

     AND (r.status_code not in (3,8) OR r.status_code IS NULL) 

     GROUP BY p.proposal_id; 

表目前看起来是这样的：

我想补充从“held_proposals”表中返回每个建议值表格的结尾作为另一列。

请问我可以提供一些关于如何在SQL查询中实现这一点的指导。先谢谢你。

Answer 1

您需要组您作为

SELECT 
p.proposal_id, 
p.proposal_title, 
p.description, 
u.user_record_id, 
u.forename, 
u.surname, 
c.course_title, coalesce(h.Held,0) as `Held`, 
GROUP_CONCAT(DISTINCT t.tag_title) AS tags 
FROM proposal p 
LEFT JOIN user u on u.user_record_id = p.user_record_id 
LEFT JOIN course_details c on c.course_code = p.course_code 
LEFT JOIN record r on r.proposal_id = p.proposal_id 
LEFT JOIN proposal_tags pt on pt.proposal_id = p.proposal_id 
LEFT JOIN tag_details t on t.tag_code = pt.tag_code 
LEFT JOIN (
    SELECT proposal_id, COUNT(*) AS Held 
    FROM held_proposals group by proposal_id 
) h on h.proposal_id = p.proposal_id 
WHERE p.source = "Supervisor" 
AND (r.status_code not in (3,8) OR r.status_code IS NULL) 
GROUP BY p.proposal_id;