新手求助各位大侠,下面这段代码老是提示列名balance无效。declare @tmp table(oid int identity(1,1),fyear int,fperiod int,fcontent nvarchar(100),fyaosufeiyong nvarchar(255),dclend decimal(18,10),dcloan decimal(18,10),dcbalance decimal(18,10))insert into @tmp(fyear,fperiod,fcontent,fyaosufeiyong,dclend,dcloan,dcbalance)
select fyear,fperiod,fcontent,b.fname,case when fdc=1 then famount else 0 end as dclend,case when fdc=-1 then famount else 0 end as dcloan,0
from gc_ItemHs a join T_yaosufeiyongxm b on(a.fYsItemid=b.fitemid)
Where fXmItemid=3839update @tmp
set dcbalance=dclend - dcloandeclare @num int
set @num=1while @num>=(select count(0) from @tmp)
begin
update @tmp
set dcbalance=dcbalance + (select balance from @tmp where oid=@num)
where oid=@num+1
set @num=@num+1
end
select * from @tmp
begin
update @tmp
set dcbalance=dcbalance + (select balance from @tmp where oid=@num)
where oid=@num+1 ------------
表名为变量时需要使用动态SQL,其基本语法如下:
--动态sql语句基本语法
1 :普通SQL语句可以用Exec执行 eg: Select * from tableName
Exec('select * from tableName')
Exec sp_executesql N'select * from tableName' -- 请注意字符串前一定要加N 2:字段名,表名,数据库名之类作为变量时,必须用动态SQL eg:
declare @fname varchar(20)
set @fname = 'FiledName'
Select @fname from tableName -- 错误,不会提示错误,但结果为固定值FiledName,并非所要。
Exec('select ' + @fname + ' from tableName') -- 请注意 加号前后的 单引号的边上加空格 当然将字符串改成变量的形式也可
declare @fname varchar(20)
set @fname = 'FiledName' --设置字段名 declare @s varchar(1000)
set @s = 'select ' + @fname + ' from tableName'
Exec(@s) -- 成功
exec sp_executesql @s -- 此句会报错 declare @s Nvarchar(1000) -- 注意此处改为nvarchar(1000)
set @s = 'select ' + @fname + ' from tableName'
Exec(@s) -- 成功
exec sp_executesql @s -- 此句正确 3. 输出参数
declare @num int,
@sqls nvarchar(4000)
set @sqls='select count(*) from tableName'
exec(@sqls)
--如何将exec执行结果放入变量中? declare @num int,
@sqls nvarchar(4000)
set @sqls='select @a=count(*) from tableName '
exec sp_executesql @sqls,N'@a int output',@num output
select @num
select fyear,fperiod,fcontent,b.fname,case when fdc=1 then famount else 0 end as dclend,case when fdc=-1 then famount else 0 end as dcloan,0
from gc_ItemHs a join T_yaosufeiyongxm b on(a.fYsItemid=b.fitemid)
Where fXmItemid=3839update @tmp
set dcbalance=dclend - dcloandeclare @num int
set @num=1while @num<(select count(0) from @tmp)
begin
update @tmp
set dcbalance=dcbalance + (select dcbalance from @tmp where oid=@num)
where oid=@num+1
set @num=@num+1
end
select * from @tmp先谢谢了。