下表显示了很多有关移调的问题…
scanid | region | volume ------------------------- 1 A 34.4 1 B 32.1 1 C 29.1 2 A 32.4 2 B 33.2 2 C 35.6
到这张表。
scanid | A_volume | B_volume | C_volume ---------------------------------------- 1 34.4 32.1 29.1 2 32.4 33.2 35.6
但是，我需要做相反的事情，并且难以解决这个问题。有人可以帮忙吗？
谢谢你。
您可以使用UNION子句非常简单地执行此操作：
Select Scan_ID, 'A' as Region, A_Volume as volume union all Select Scan_ID, 'B' as Region, B_Volume as volume union all Select Scan_ID, 'C' as Region, C_Volume as volume
