在表中加入多列

Question

我有2个表[table1，table2]

Table 1
+----+------------+
| id | name       |
+--+--------------+
|  2 | Film       |
|  1 | Music      |
|  3 | OTHER      |
|  5 | Sports     |
|  4 | TV Content |
+----+------------+

Table 2
+----+-----+-----+
| id | id1 | id2 |
+----+-----+-----+
|  2 |   1 |   1 |
|  1 |   1 |   1 | 
|  3 |   2 |   1 |
|  5 |   3 |   1 |
|  4 |   4 |   1 |
+----+-----+-----+

我想要的输出是

+------------+------------+----------+
| id_name    | id1_name   | id2_name |
+------------+------------+----------+
| film       | Music      | Music    |
| music      | Music      | Music    | Required Output
| other      | Film       | Music    |
| sports     | OTHER      | Music    |
| TV Content | TV Content | Music    |
+------------+------------+----------+

我该怎么做？

Answer 1

由于您有三个不同的外键，您需要使用同一个表执行3个不同的连接：

SELECT table1.name AS 'id_name',
       first.name AS 'id1_name',
       second.name AS 'id2_name'
FROM table2
    JOIN table1 ON
        table1.id = table2.id
    JOIN table1 first ON
        first.id = table2.id1
    JOIN table1 second ON
        second.id = table2.id2