ISO 语法
DECLARE cursor_name [ INSENSITIVE ] [ SCROLL ] CURSOR 
     FOR select_statement 
     [ FOR { READ ONLY | UPDATE [ OF column_name [ ,...n ] ] } ]
[;]


Transact-SQL 扩展语法
DECLARE cursor_name CURSOR [ LOCAL | GLOBAL ] （说明游标的“作用域”）
     [ FORWARD_ONLY | SCROLL ] （说明游标的“方向”）
     [ STATIC | KEYSET | DYNAMIC | FAST_FORWARD ] （“说明游标的“类型”）
     [ READ_ONLY | SCROLL_LOCKS | OPTIMISTIC ] 
     [ TYPE_WARNING ] 
     FOR select_statement 
     [ FOR UPDATE [ OF column_name [ ,...n ] ] ]
[;] 

declare testcur cursor --声明时未指定"local"或"global"关键字,系统默认游标是"global(全局)"的.
for 
select 学号,姓名 from XSB
GO
open testcur   
fetch next from testcur
GO
--------------------------------------------
declare testcur cursor local   --声明时指定"local"关键字
for 
select 学号,姓名 from XSB
open testcur   
fetch next from testcur
GO    --在这个批处理结束后,游标自动释放,即失效
-----------------------------------------------
declare testcur1 cursor local  --声明时指定"local"关键字
for 
select 学号,姓名 from XSB
GO  --在这个批处理后,游标就失效了,后面对游标操作时,提示"名为 ‘testcur1‘ 的游标不存在"错误.
open testcur1   
fetch next from testcur1
GO

declare directionCur cursor --不指定移动方向，则默认为“forward_only”
for
select 学号,姓名 from XSB
Go
open directionCur
fetch next from directionCur
Go
fetch prior from directionCur --错误“提取类型 prior 不能与只进游标一起使用。”
Go
close directionCur2
deallocate directionCur2
Go
-----------------------------------------
declare directionCur1 cursor forward_only --指定“forward_only”方向
for
select 学号,姓名 from XSB
Go
open directionCur1
fetch next from directionCur1
Go
fetch prior from directionCur1 --错误“提取类型 prior 不能与只进游标一起使用。”
Go
close directionCur2
deallocate directionCur2
Go
-----------------------------------------
declare directionCur2 cursor scroll --指定“scroll”方向
for
select 学号,姓名 from XSB
Go
open directionCur2
fetch next from directionCur2
Go
fetch prior from directionCur2
Go
close directionCur2
deallocate directionCur2
Go
---------------------------------
--结论:若游标没有指定任何访问或类型参数,则默认为全局、只进、动态游标。（这是在SQLServer2008 R2上的测试结果，具体取决于软件设置）

--"scroll"和"fast_forward"不能一起使用
declare forwardTest cursor scroll fast_forward  --报错“游标选项 SCROLL 和 FAST_FORWARD 冲突。”
for
select 学号,姓名 from XSB
Go

--在 SQL Server 2000 中，FAST_FORWARD 和 FORWARD_ONLY 游标选项是互相排斥的。如果指定了二者，则会引发错误。
--在 SQL Server 2005 及更高版本中，这两个关键字可以用在同一个 DECLARE CURSOR 语句中。
declare forwardTest1 cursor forward_only fast_forward
for 
select * from XSB
Go

OPEN { { [ GLOBAL ] cursor_name } | cursor_variable_name }

--打开游标并读取所有行
declare XSBcur cursor --声明
for 
Select * from XSB 
Go
open XSBcur  --打开
fetch next from XSBcur --获取数据
while @@FETCH_STATUS = 0
begin
fetch next from XSBcur
end
close XSBcur --关闭
deallocate XSBcur --删除

FETCH 
          [ [ NEXT | PRIOR | FIRST | LAST 
                    | ABSOLUTE { n | @nvar } 
                    | RELATIVE { n | @nvar } 
               ] 
               FROM 
          ] 
{ { [ GLOBAL ] cursor_name } | @cursor_variable_name } 
[ INTO @variable_name [ ,...n ] ] --into说明将读取的游标数据存放到指定的变量中

-----------------------------------
declare stuCur cursor scroll
for 
select 学号,姓名 from XSB
GO
open stuCur 
Go
--读取数据开始
fetch next from stuCur --读取当前行的下一行，并使其置为当前行(刚开始时游标置于表头的前一行，即若表是从0开始的，游标最初置于-1处，所以第一次读取的是头一行)
fetch prior from stuCur --读取当前行的前一行，并使其置为当前行
fetch first from stuCur --读取游标的第一行，并使其置为当前行（不能用于只进游标）
fetch last from stuCur  --读取游标的最后一行，并使其置为当前行（不能用于只进游标）
fetch absolute 2 from stuCur --读取从游标头开始向后的第2行，并将读取的行作为新的行
fetch relative 3 from stuCur --读取从当前行开始向后的第3行，并将读取的行作为新的行
fetch relative-2 from stuCur --读取当前行的上两行，并将读取的行作为新的行
--读取数据结束
GO
close stuCur 
Go
deallocate stuCur
Go
---------------------------

CLOSE { { [ GLOBAL ] cursor_name } | cursor_variable_name }

close stuCur --若该游标事先声明并已打开
Go

DEALLOCATE { { [ GLOBAL ] cursor_name } | @cursor_variable_name }

--声明一个游标
declare abc cursor scroll 
for
select * from XSB

--(1)通过名称,使用set语句将游标设置为游标变量
declare @mycur cursor
set @mycur = abc

--(2)也可以不定义游标名称而创建游标并将其与变量关联
declare @mycursor cursor
set @mycursor = cursor local scroll for
Select * from XSB

declare @mycur cursor
set @mycur = cursor local scroll for
select * from XSB
 
deallocate @mycur

set @mycur = cursor local scroll for
select * from XSB
GO
--不必显式释放游标变量。变量在离开作用域时被隐式释放。

USE AdventureWorks2008R2;
GO
-- Create and open a global named cursor that
-- is visible outside the batch.
DECLARE abc CURSOR GLOBAL SCROLL FOR
SELECT * FROM Sales.SalesPerson;
OPEN abc;
GO
-- Reference the named cursor with a cursor variable.
DECLARE @MyCrsrRef1 CURSOR;
SET @MyCrsrRef1 = abc;
-- Now deallocate the cursor reference.
DEALLOCATE @MyCrsrRef1;
-- Cursor abc still exists.
FETCH NEXT FROM abc;
GO
-- Reference the named cursor again.
DECLARE @MyCrsrRef2 CURSOR;
SET @MyCrsrRef2 = abc;
-- Now deallocate cursor name abc.
DEALLOCATE abc;
-- Cursor still exists, referenced by @MyCrsrRef2.
FETCH NEXT FROM @MyCrsrRef2;
-- Cursor finally is deallocated when last referencing
-- variable goes out of scope at the end of the batch.
GO
-- Create an unnamed cursor.
DECLARE @MyCursor CURSOR;
SET @MyCursor = CURSOR LOCAL SCROLL FOR
SELECT * FROM Sales.SalesTerritory;
-- The following statement deallocates the cursor
-- because no other variables reference it.
DEALLOCATE @MyCursor;
GO

CREATE TABLE [dbo].[XSB](
    [学号] [char](6) NOT NULL,
    [姓名] [char](8) NOT NULL,
    [性别] [bit] NULL,
    [出生时间] [date] NULL,
    [专业] [char](12) NULL,
    [总学分] [int] NULL,
    [备注] [varchar](500) NULL,
PRIMARY KEY CLUSTERED 
(
    [学号] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]

GO

insert into XSB values
(‘081101‘,‘王林‘,‘true‘,‘1990-2-10‘,‘计算机‘,50,null),
(‘081102‘,‘陈平‘,‘true‘,‘1991-2-1‘,‘计算机‘,50,null),
(‘081103‘,‘王燕‘,‘false‘,‘1989-10-6‘,‘计算机‘,50,null),
(‘081104‘,‘韦严平‘,‘true‘,‘1990-8-26‘,‘计算机‘,50,null),
(‘081106‘,‘李芳芳‘,‘true‘,‘1990-11-20‘,‘计算机‘,50,null),
(‘081107‘,‘李明‘,‘true‘,‘1990-5-1‘,‘计算机‘,54,‘已提前修完数据结构,并获学分‘),
(‘081108‘,‘林一凡‘,‘true‘,‘1989-8-5‘,‘计算机‘,52,‘已提前修完一门课‘),
(‘081109‘,‘张强民‘,‘true‘,‘1989-8-11‘,‘计算机‘,50,null),
(‘081110‘,‘张蔚‘,‘false‘,‘1991-7-22‘,‘计算机‘,50,‘三好生‘),
(‘081111‘,‘赵琳‘,‘false‘,‘1989-10-6‘,‘计算机‘,50,null),
(‘081113‘,‘严红‘,‘false‘,‘1989-8-11‘,‘计算机‘,48,‘一门不及格，待补考‘),
(‘081201‘,‘王敏‘,‘true‘,‘1989-6-10‘,‘通信工程‘,42,null),
(‘081202‘,‘王林‘,‘true‘,‘1989-6-10‘,‘通信工程‘,40,‘一门不及格，待补考‘)
GO