deallocate(存储过程中游标是怎么用的)

• 1、deallocate，存储过程中游标是怎么用的？
• 2、关于空气污染的英语作文？
• 3、sql怎么使用自定义函数来查询？

1、deallocate，存储过程中游标是怎么用的？

ALTERproc[dbo].[存储过程名]asbegindeclare游标名字cursorforselect列名from表名where条件--先申明游标指向查询出的结果，一列，或者多列都可以，条件自定declare变量名varchar(400)--存储取到的值open游标名--开启游标while@@FETCH_STATUS=0--取值beginfetchnextFROM游标名into变量名--这样就将游标指向下一行，得到的第一行值就传给变量了---------------------------------------------需要执行的操作，例如修改某表中的字段update表名set列名=值where（修改表中的列）=变量名-------------------------------------------endclose游标名--关闭游标deallocate游标名--释放游标end

2、关于空气污染的英语作文？

Air pollution is one of the major problems of the modern world. A great deal of energy is needed to run the factories of modern industrial nations. Automobile, trains, planes and busses need energy, too. Nearly all of this energy is produced by burning fuels. The burning produces wastes, some of which remain in the air, causing air pollution. Scientists are finding ways to stop air pollution especially in big industrial areas and densely-populated cities. They are studying new ways of generating electricity that may be less damaging to the environment. In the meantime, many power plants are being modernized to give off less polluted material. Also, engineers try to design and locate new power plants to do minimum damage to the environment. However, it may be that we still have a long way to go before we have a "clean" world. Nearly all of the countries are trying hard to prevent and control air pollution. There indeed seems to be no end to tasks that environmentalists will be required to do. People will continually find new ways to control pollution.

3、sql怎么使用自定义函数来查询？

用游标: declare @变量1 varchar(50),@变量2 varchar(50) -----创建游标 declare mycurs cursor for select 字段A,字段B from table1 open mycurs-----打开游标 fetch next from mycurs into @变量1,变量2 while @@fetch_Status=0--循环游标 begin ---循环处理 fetch next from mycurs into @变量1,变量2 end close mycurs Deallocate mycurs 我说的可能不好，你自己去可以看看游标的相关资料。