22,300
社区成员




Create Proc DisTest(
@Filter varchar (1024), --筛选条件
@RpFliedName varchar (1024), --重复字段名
@KeyName varchar (1024), --要删除重复的表的主键名称
@TableName varchar (1024), --要删除重复的表的表名称
@DelFilter varchar (1024) --删除条件
)
as
begin
Declare @userId varchar (1024)
Declare @MarkId int
Declare @Pcount int
exec ('Declare exam_mark_cur cursor for
select '+@RpFliedName+' from '+@TableName+
' where '+@Filter+' group by '+@RpFliedName+
' having count('+@RpFliedName+')>1'
)
OPEN exam_mark_cur
FETCH NEXT from exam_mark_cur INTO @userId
WHILE @@FETCH_STATUS = 0
BEGIN
EXEC('Declare current_cur cursor for
select '+@KeyName+' from '+@TableName+' where '+@RpFliedName+' =@userId')
OPEN current_cur
FETCH NEXT from current_cur INTO @MarkId
WHILE @@FETCH_STATUS = 0
BEGIN
exec('
select @Pcount=count(*) from '+@TableName+' where '+@RpFliedName+' =@userId')
IF @Pcount=1
break
exec('delete from '+@TableName+' where '+@KeyName+'=@MarkId '+@DelFilter)
FETCH NEXT from current_cur INTO @MarkId
END
CLOSE current_cur
DEALLOCATE current_cur
FETCH NEXT from exam_mark_cur INTO @userId
END
CLOSE exam_mark_cur
DEALLOCATE exam_mark_cur
end
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