條件運算符

Question

源

ename location sal 
A  X   10 
A  x   20 
B  y   30 
B  x   40 

ref_table

參考

ename location sal hike 
A  x   '<30' 10% 
B  y   '>30' 25% 

對於Ref_table的第一個記錄我的邏輯應

Select Sal 
from source a 
left join 
Ref_table B 
where 
a.sal<=B.sal 

對於Ref_table的第二記錄米Ÿ邏輯應該

Select Sal 
from source a 
left join 
Ref_table B 
where 
a.sal>=B.sal 

Answer 1

試試這個：

select Sal 
from source a 
left join Ref_table B on case when substring(B.Sal,1,1)='<' and a.sal<=cast(substring(B.sal,2,10) as int) then 1 when substring(B.Sal,1,1)='>' and a.sal>=cast(substring(B.sal,2,10) as int) then 1 else 0 end=1 

另外要小心，因爲你用左連接並在其中將只返回滿足您的條件（類似於內部連接）行。

Answer 2

試試這個：

select 
    s.sal, 
    s.ename 
from 
    source s inner join 
    ref_table r on 
    s.ename = r.ename 
where 
    (ename = 'a' and s.sal<=r.sal) or 
    (ename = 'b' and s.sal>=s.sal)