SQL - 如何列出值大于另一个单元格的单元格？

Question

我有以下数据库,我需要列出配额大于subno 30012配额的所有subno,subname.

subno   subname                 quota
30006   Adv Database design 300
30007   Software fundamentals   200
30008   Application Development 350
30010   Database development    300
30011   System design           200
30012   Requirement engineering 350

我知道我能做到

select subno, subname from subject
where quota > 350

但是如何更改此配置以允许配额大于30012的配额而不是大于350？

Answer 1

您使用子查询:

select subno, subname from subject
where quota > (select quota from subject where subno = 30012)

这假定给定的只有一个可能的引用subno.如果可能有多个,则使用聚合函数,例如:

select subno, subname
from subject
where quota > (select max(quota) from subject where subno = 30012)