我希望每个 ID 有 2 个 Custom_Column 值。
我怎样才能做到这一点？
示例表:
ID
1
2
3
示例查询:
SELECT id, (id*2) as Custom_Value, (id*4) as Custom_Value FROM numbers
回应:
ID Custom_Value
1 2
1 4
2 4
2 8
3 6
3 12
最佳答案
使用UNION
SELECT ID, (ID*2) as CustomVal FROM tableNAme
UNION ALL
SELECT ID, (ID*4) as CustomVal FROM tableNAme
ORDER BY ID
关于mysql - 自定义列的多个值，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/14373438/