Question

我有两个名为customers和orders的MySQL数据库表，下面有一个示例......

customers
client_id | cust_name | cust_phone
--------------------------------
8273      | Mr Jones  | 382749584
38        | Mr Smith  | 773625372
9         | Mrs Brown | 922382938

orders
order_id | cust_id  | product_id
--------------------------------
392      | 9        | 9388
23       | 2837     | 9283
488      | 17       | 28392

我正试图像这样做一个INNER JOIN ......

SELECT * FROM customers
JOIN orders
ON customers.cust_id=orders.client_id
WHERE ('client_id' LIKE '9')

它没有返回任何结果，但我希望它能显示client_id为9的字段

我哪里错了？

Answer 1

您的查询错误。

SELECT * FROM customers
JOIN orders
ON customers.client_id =orders.cust_id
WHERE ('client_id' LIKE '9')

列client_id并不存在于orders表中。使用client_id = 9代替like查询。

Answer 2

我认为你在这里犯了错误＆＃39; client_id＆＃39;

SELECT * FROM customers
JOIN orders
ON customers.cust_id=orders.client_id
WHERE client_id LIKE '9'

如果你写'＆＃39;＆＃39;它取为字符串

Answer 3

尝试这个完全匹配

SELECT * FROM customers JOIN orders ON customers.cust_id=orders.client_id WHERE orders.client_id = 9

或类似

SELECT * FROM customers JOIN orders ON customers.cust_id=orders.client_id WHERE orders.client_id Like '9'

这里可以使用

外卡字符，例如

'%9%' 
'9%'

MySQL内部联接 - 不返回任何结果

3 个答案: