Question

我有两个表issue_details和payees，如下所示，值为：

表： issue_details

+----------+------------+----------+----------+
| check_no | issue_date | payee_id | lddap_no | 
+----------+------------+----------+----------+
|        0 | 2015-01-01 |          | 11101-15 | 
|        1 | 2015-01-24 |          | 11101-15 |
|    34561 | 2015-01-24 | 10       |          |
|    34562 | 2015-01-24 | 13       |          | 
+----------+------------+----------+----------+

表：收款人

+----------+--------------------+
| payee_id | payee_name         | 
+----------+--------------------+
| 1        | John Smith         | 
| 10       | Chen Lou           | 
| 11       | Mark Dello         |
| 12       | ANTRECCO           | 
| 13       | Shay Ridz          | 
+----------+--------------------+

我执行此查询以连接两个表来描述我的issue_details表中的收款人姓名。

SELECT      
    issue_details.issue_date AS date,
    issue_details.check_no AS check_no,
    payees.payee_name AS payee 
FROM
    issue_details
INNER JOIN 
    payees ON issue_details.payee_id = payees.payee_id

结果：

+----------+------------+----------+
| check_no | issue_date | payee    | 
+----------+------------+----------+
|    34561 | 2015-01-24 | Chen Lou |       
|    34562 | 2015-01-24 | Shay Ridz|       
+----------+------------+----------+

如果我这样做：

SELECT      
    issue_details.issue_date AS date,
    issue_details.check_no AS check_no,
    CONCAT(payees.payee_name, '', lddap_no) AS payee 
FROM
    issue_details
INNER JOIN 
    payees ON issue_details.payee_id = payees.payee_id

结果仍然如上。它没有连接两列 payee_name（从表收款人加入）和lddap_no。

这就是我想要发生的事情：

+----------+------------+----------+
| check_no | issue_date | payee    |  
+----------+------------+----------+
|        0 | 2015-01-01 | 11101-15 |      
|        1 | 2015-01-24 | 11101-15 |     
|    34561 | 2015-01-24 | Chen Lou |
|    34562 | 2015-01-24 | Shay Ridz|     
+----------+------------+----------+

请在这里帮助我查询。非常感谢。感谢

Answer 1

SELECT      id.issue_date AS date,
            id.check_no AS check_no,
            COALESCE( p.payee_name, id.lddap_no ) AS payee 
FROM        issue_details id
            LEFT  JOIN payees p ON
            id.payee_id = p.payee_id

请参阅SQLFiddle Demo

Answer 2

只需将INNER JOIN更改为LEFT JOIN

即可

SELECT      issue_details.issue_date AS date,
            issue_details.check_no AS check_no,
            payees.payee_name AS payee 
FROM
            issue_details
            LEFT JOIN payees ON
            issue_details.payee_id = payees.payee_id

如何在mysql中将两列与连接表连接起来

2 个答案: