这个按月统计怎么写

SQL code

create table S1(sheet_no int identity(1,1) ,pname nvarchar(10),oper_date datetime,amt decimal(18,1),paid decimal(18,1))insert into S1  (pname,oper_date,amt,paid) values ('01','2012-02-01',60,5)insert into S1  (pname,oper_date,amt,paid) values ('01','2012-01-11',70,0)insert into S1  (pname,oper_date,amt,paid) values ('01','2012-02-21',80,0)insert into S1  (pname,oper_date,amt,paid) values ('01','2012-03-01',90,15)insert into S1  (pname,oper_date,amt,paid) values ('02','2012-02-01',81,0)insert into S1  (pname,oper_date,amt,paid) values ('02','2012-03-01',85,16)insert into S1  (pname,oper_date,amt,paid) values ('03','2012-01-11',80,0)insert into S1  (pname,oper_date,amt,paid) values ('03','2012-03-01',90,20)

pname 名称 amt 单据金额 paid 已付金额

实现效果
名称总额余额1月已付金额2月已付金额3月已付金额
01
02
03


[解决办法]
--不明白你的余额是怎么算算出来的.

SQL code

create table S1(sheet_no int identity(1,1) ,pname nvarchar(10),oper_date datetime,amt decimal(18,1),paid decimal(18,1))insert into S1  (pname,oper_date,amt,paid) values ('01','2012-02-01',60,5)insert into S1  (pname,oper_date,amt,paid) values ('01','2012-01-11',70,0)insert into S1  (pname,oper_date,amt,paid) values ('01','2012-02-21',80,0)insert into S1  (pname,oper_date,amt,paid) values ('01','2012-03-01',90,15)insert into S1  (pname,oper_date,amt,paid) values ('02','2012-02-01',81,0)insert into S1  (pname,oper_date,amt,paid) values ('02','2012-03-01',85,16)insert into S1  (pname,oper_date,amt,paid) values ('03','2012-01-11',80,0)insert into S1  (pname,oper_date,amt,paid) values ('03','2012-03-01',90,20)select pname 名称,       sum(amt) 单据金额,       sum(case datepart(mm,oper_date) when 1 then paid else 0 end) [1月已付金额],       sum(case datepart(mm,oper_date) when 2 then paid else 0 end) [2月已付金额],       sum(case datepart(mm,oper_date) when 3 then paid else 0 end) [3月已付金额]from s1group by pnamedrop table s1/*名称         单据金额                                     1月已付金额                                   2月已付金额                                   3月已付金额                                   ---------- ---------------------------------------- ---------------------------------------- ---------------------------------------- ---------------------------------------- 01         300.0                                    .0                                       5.0                                      15.002         166.0                                    .0                                       .0                                       16.003         170.0                                    .0                                       .0                                       20.0（所影响的行数为 3 行）*/