php - LEFT JOIN 两个具有相同列名的表并用 PHP 打印它们

Question

我的 MySQL 数据库中有两个表：

USERS ('id_user' - 'id_client' -> the same as the id in CLIENTS)
CLIENTS ('id_client' - 'name' etc.)

我想打印所有客户和各自的用户。这是我的查询：

SELECT * FROM clients AS c LEFT JOIN users AS u ON c.id_client = u.id_client

似乎没问题，但是当我尝试id_client从 table打印 the 时遇到了麻烦clients。如何使用 PHP 打印它们？看来他们是空的......我的查询错了吗？

Answer 1

尝试，

需要 GROUP BY 或 DISTINCT

    SELECT * FROM clients AS c LEFT JOIN users AS u ON c.id_client = u.id_client GROUP BY c.id_client

Answer 2

比这更简单，只需执行以下操作：

SELECT c.*, u.name FROM clients AS c LEFT JOIN users AS u ON c.id_client = u.id_client

这将从表 c 中选择所有内容，并且仅从表 u 中选择名称。您遇到的问题是您正在从两个表中选择 id_client，这不是必需的，并且在尝试使用 php.ini 引用它时会导致混淆。

Answer 3

由于您在两个表中都有相同名称的字段（“id_client”），因此您必须指定要打印的字段。

像这样：

SELECT u.id_client, c.id_client, ... FROM clients AS c LEFT JOIN users AS u ON c.id_client = u.id_client

Answer 4

选择 c。,u。FROM clients c LEFT external JOIN users u ON c.id_client = u.id_client