Question

出于某种原因，我无法完成这项工作：

我有两张桌子。首先叫做任务：

id     name         project_id     list_id
==========================================
1      First Task   1              1

第二个名为Lists：

id    project_id     name          position
===========================================
1     1              My List       1
2     2              Second List   2

这是我的疑问：

SELECT 
  tl.*,
  COUNT(t.id) AS total 
FROM
  lists AS tl 
  LEFT JOIN tasks AS t 
    ON tl.id = t.list_id 
WHERE tl.project_id = 1
ORDER BY tl.position;

并且无论我总是以0总计结束

这里是结果数组

Array
(
    [0] => stdClass Object
        (
            [id] => 1
            [project_id] => 1
            [name] => My List
            [position] => 1
            [total] => 0
        )

)

[total] => 0的值应为[total] => 1

Answer 1

我在Where子句中使用了错误的ID。它被硬编码为1，它应该是动态的，从URL获取。

Php，mysql连接和计数记录

1 个答案: