11.14 游标【笔记】

游标：是过程化思维
基本语法
1.delcare 游标名 cursor[local|global][游标选项]
for  查询语句
2.open 游标名
3.feth
（1）定义
delcare cur_MyStudent cursor  fast_forward
for select * from MyStudent
-----查询会返回结果集（基于返回的结果集）
（2）打开
open cur_MyStudent
(3)操作
fetch next from  cur_MyStudent
while  @@fetch_status=0
begin
fetch next from  cur_MyStudent
end
(4)关闭
close  cur_MyStudent
(5)释放游标
deallocate cur_MyStudent
------------------
-----将老师的工资更新，更新后的金额为原来的工资加上奖金
1.定义两个变量，来存放TblTeacherSalary表中的
tTId和reward
declare @id  int
declare @reward money
declare  cur_Reward cursor  fast_forword
for-----基于查询的数据集
select tTId ,reward   from TblTeacherSalary
open cur_Reward
fetch next from cur_Reward into @id,@reward
while @@fetch_status=0
begin
update TblTeacher set tTSalary=tTSalary+@reward
where tTId=@id
end
close cur_Reward
deallocate cur_Reward
2.把奖金设置为工资的0.1倍
declare @sid  int
declare @salary money
declare cur_Reward2  cursor fast_forward
for
select tTId   from TblTeacherSalary
open cur_Reward2
fetch next from cur_Reward2 into @sid
while @@fetch_status=0
begin
---set @salary=(select tTSalary from Tblteacher)
select @salary =tTsSalary from TblTeacher
更新奖金表
update  TblTeacherSalary set reward=@salary*0.1
where current  of cur_Reward2
fetch next from cur_Reward2 into @sid
end

close cur_Reward2
deallocate cur_Reward2