Question

对于我几乎完成的几个表，我有一个相当复杂的查询。最后一个方面只是汇总一个项目收到的投标数量，但我正在为特定部分中的所有项目执行此操作。查询工作正常，但我尝试将聚合（/ * * /）添加到查询时只返回1行。阅读它似乎我需要一个子查询，除了我不完全确定如何去做。这是迄今为止的查询：

SELECT s.id as section_id, s.name as section, i.id as item_id, 
i.title as item_title, item.location_id as item_location_id,
i.slug as item_slug, i.description as item_description, 
i.price as item_price, UNIX_TIMESTAMP(i.date_added) as item_date_added, 
c.id, c.city, c.particular_id, p.id, p.particular /*,COUNT(o.i_id) as interest*/

FROM section as s
INNER JOIN item as i
ON s.id = i.section_id
INNER JOIN city as c
ON i.location_id = c.id
INNER JOIN particular as p
ON c.particular_id = p.id

/*LEFT JOIN offer as o
ON o.job_id = i.id*/

WHERE s.id = 2

代码的工作原理是它返回我预期的所有行，直到引入/ * * /代码，现在它只返回1行。

你能给我的任何帮助都将不胜感激

由于

强尼

Answer 1

如果你正在进行聚合，你必须有分组，例如：

     SELECT s.name, COUNT(i.id)
       FROM section as s
 INNER JOIN item as i
   GROUP BY s.name

将返回部分名称和在其中找到的项目数。

Answer 2

它应该可以解决你的问题：

SELECT s.id as section_id, s.name as section, i.id as item_id, 
    i.title as item_title, item.location_id as item_location_id,
    i.slug as item_slug, i.description as item_description, 
    i.price as item_price, UNIX_TIMESTAMP(i.date_added) as item_date_added, 
    c.id, c.city, c.particular_id, p.id, p.particular,
    (SELECT COUNT(o.i_id) FROM offer AS o ON o.job_id = i.id) AS interest
FROM section as s
INNER JOIN item as i
    ON s.id = i.section_id
INNER JOIN city as c
    ON i.location_id = c.id
INNER JOIN particular as p
    ON c.particular_id = p.id
WHERE s.id = 2

Mysql COUNT子查询

2 个答案: