根据另一列的数据从MySQL表中获取数据的正确方法是什么？移调？

Question

我有一个表是这样的：

idstable 
+--------+-----+-----+-----+-----+-----+ 
| userid | id1 | id2 | id3 | id4 | id5 | 
+--------+-----+-----+-----+-----+-----+ 
| 1 | 6 | 2 | 52 | 32 | 16 | 
+--------+-----+-----+-----+-----+-----+ 
| 2 | 12 | 5 | 18 | 21 | 5 | 
+--------+-----+-----+-----+-----+-----+ 
| ... | ... | ... | ... | ... | ... | 

我想获取存储在列中的ID号，并从他们的另一个表中获取行。我希望从获得行的表是：

namestable 
+----+----------+ 
| id | name | 
+----+----------+ 
| 6 | Bruce | 
+----+----------+ 
| 2 | Mary | 
+----+----------+ 
| 52 | Dick | 
+----+----------+ 
| 32 | Bob | 
+----+----------+ 
| 16 | Jack | 
+----+----------+ 
| .. | ... | 

结果集我是我尝试得到的是这样的：

+------+----+-------+ 
| User | id | name | 
+------+----+-------+ 
| 1 | 6 | Bruce | 
+------+----+-------+ 
| 1 | 2 | Mary | 
+------+----+-------+ 
| 1 | 52 | Dick | 
+------+----+-------+ 
| 1 | 32 | Bob | 
+------+----+-------+ 
| 1 | 16 | Jack | 
+------+----+-------+ 

我如何可以查询idstable一个用户ID来检索与之关联的ID，然后从namestable中检索正确的行？我读过这个称为转置，但我还没有找到一个简洁的例子。

任何想法？

Answer 1

join

SELECT idstable.id as User, namestable.id as id, namestable.name as name 
FROM idstable it 
JOIN namestable nt on (nt.id = it.id1 or nt.id = it.id2 ... 3,4,5 like the first two) 

理想情况下，你的idstable不会有5列，但每ID为5行。