BookInfo 表是图书信息表,如下:Id
Category
Name
...LoanBook 表是借阅表,如下:Id
BookId //外键
userId
...现在想取得借出书最多的书的信息和分别的借阅次数,
于是自己写的一个存储过程如下:
create procedure SelectLendingList
@qty int
as
begin
select top (@qty) *,BookId,num from BookInfo where BookInfo.Id=BookId and BookId
in(select BookId ,count(distinct(BookId)) as num from LoanBook group by BookId order by num desc)
end但是出现了下面错误:
除非另外还指定了 TOP 或 FOR XML,否则,ORDER BY 子句在视图、内联函数、派生表、子查询和公用表表达式中无效。
还望高手纠正,和支持上述错误原因,感激涕零
Category
Name
...LoanBook 表是借阅表,如下:Id
BookId //外键
userId
...现在想取得借出书最多的书的信息和分别的借阅次数,
于是自己写的一个存储过程如下:
create procedure SelectLendingList
@qty int
as
begin
select top (@qty) *,BookId,num from BookInfo where BookInfo.Id=BookId and BookId
in(select BookId ,count(distinct(BookId)) as num from LoanBook group by BookId order by num desc)
end但是出现了下面错误:
除非另外还指定了 TOP 或 FOR XML,否则,ORDER BY 子句在视图、内联函数、派生表、子查询和公用表表达式中无效。
还望高手纠正,和支持上述错误原因,感激涕零
@qty int
as
begin
select top (@qty) *,BookId,num from BookInfo where BookInfo.Id=BookId and BookId
in(select top 100 percent BookId ,count(distinct(BookId)) as num from LoanBook group by BookId order by num desc)
end
@qty int
as
begin
select top (@qty) *,BookId,num from BookInfo where BookInfo.Id=BookId and BookId
in(select BookId from LoanBook)
end在这种情况下只需这样。
--看看我的。
create procedure SelectLendingList
@qty int
as
begin
exec('select top '+@qty+' * from
(select a.bookid,b.name,count(1) num from LoanBook a,BookInfo b where a.bookid=b.id group by a.bookid,b.name) c
order by c.num desc,c.bookid,c.name')
end
create procedure SelectLendingList
@qty int
as
begin
exec('select top '+@qty+' * from
(select a.bookid,b.name,count(a.bookid) num from LoanBook a,BookInfo b where a.bookid=b.id group by a.bookid,b.name) c
order by c.num desc,c.bookid,c.name')
end
还是和直接那样执行没什么区别呢?
1 :普通SQL语句可以用Exec执行 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 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