sqlserver查询语句

[待解决问题]

select * from (
select year,case when t.month=1 then (select amount from mm s where s.year=t.year and s.month=1) end as m1,
case when t.month=2 then (select amount from mm s where s.year=t.year and s.month=2) end as m2,
case when t.month=3 then (select amount from mm s where s.year=t.year and s.month=3) end as m3,
case when t.month=4 then (select amount from mm s where s.year=t.year and s.month=4) end as m4
from mm t) g

请问想要得到这种格式需要怎么修改一下

--year m1 m2 m3 m4
--1991 1.1 1.2 1.3 1.4
--1992 2.1 2.2 2.3 2.4