year mon sum
-------------------------
1999 1 1.1
1999 2 1.2
1999 3 1.3
1999 4 1.4
2000 1 2.1
2000 2 2.2
2000 3 2.3
2000 4 2.4写一个查询语句,结果为:year m1 m2 m3 m4
----------------------------------
1999 1.1 1.2 1.3 1.4
2000 2.1 2.2 2.3 2.4这个sql改怎么写?
-------------------------
1999 1 1.1
1999 2 1.2
1999 3 1.3
1999 4 1.4
2000 1 2.1
2000 2 2.2
2000 3 2.3
2000 4 2.4写一个查询语句,结果为:year m1 m2 m3 m4
----------------------------------
1999 1.1 1.2 1.3 1.4
2000 2.1 2.2 2.3 2.4这个sql改怎么写?
[year],
sum(case [mon] when 1 then [sum] else 0 end) as m1,
sum(case [mon] when 2 then [sum] else 0 end) as m2,
sum(case [mon] when 3 then [sum] else 0 end) as m3,
sum(case [mon] when 4 then [sum] else 0 end) as m4
from tb
group by [year]