[SQL Server]游标示例

 --创建测试临时表
IF(OBJECT_ID('tempdb..#Books') IS NOT NULL)
BEGIN
            DROP TABLE #Books;
END

CREATE TABLE #Books
(
           BookName NVARCHAR(20),
           BookCode NVARCHAR(20)
)

INSERT INTO #Books( BookName, BookCode ) VALUES(N'C# 本质论','JC556874');
INSERT INTO #Books( BookName, BookCode ) VALUES(N'JS 本质论','JS556874');

--申明一个游标
DECLARE MyCursor CURSOR FOR
                    SELECT TOP 5 BookName,BookCode FROM #Books;

--打开一个游标 
OPEN MyCursor;

DECLARE @BookName nvarchar(20);
DECLARE @BookCode nvarchar(20);

--循环一个游标
FETCH NEXT FROM MyCursor INTO @BookName,@BookCode;
WHILE(@@FETCH_STATUS = 0)
BEGIN
            PRINT('Book Name: '+@BookName);
            FETCH NEXT FROM  MyCursor INTO @BookName,@BookCode;
END 

--关闭游标
CLOSE MyCursor;
--释放资源
DEALLOCATE MyCursor;

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@@FETCH_STATUS 是一个全局变量，其值有以下三种 ：
1)  0 FETCH 语句成功
2) -1 FETCH 语句失败或此行不在结果集中
3) -2 被提取的行不存在