标签:
本人收集的,挺有用的
1. 利用游标循环更新、删除MemberAccount表中的数据
DECLARE My_Cursor CURSOR --定义游标 FOR (SELECT * FROM dbo.MemberAccount) --查出需要的集合放到游标中 OPEN My_Cursor; --打开游标 FETCH NEXT FROM My_Cursor ; --读取第一行数据 WHILE @@FETCH_STATUS = 0 BEGIN --UPDATE dbo.MemberAccount SET UserName = UserName + ‘A‘ WHERE CURRENT OF My_Cursor; --更新 --DELETE FROM dbo.MemberAccount WHERE CURRENT OF My_Cursor; --删除 FETCH NEXT FROM My_Cursor; --读取下一行数据 END CLOSE My_Cursor; --关闭游标 DEALLOCATE My_Cursor; --释放游标 GO
2.利用游标循环更新MemberService表中的数据(更新每个用户所购买服务的时间)
DECLARE @UserId varchar(50) DECLARE My_Cursor CURSOR --定义游标 FOR (SELECT UserId FROM dbo.MemberAccount) --查出需要的集合放到游标中 OPEN My_Cursor; --打开游标 FETCH NEXT FROM My_Cursor INTO @UserId; --读取第一行数据(将MemberAccount表中的UserId放到@UserId变量中) WHILE @@FETCH_STATUS = 0 BEGIN PRINT @UserId; --打印数据(打印MemberAccount表中的UserId) UPDATE dbo.MemberService SET ServiceTime = DATEADD(Month, 6, getdate()) WHERE UserId = @UserId; --更新数据 FETCH NEXT FROM My_Cursor INTO @UserId; --读取下一行数据(将MemberAccount表中的UserId放到@UserId变量中) END CLOSE My_Cursor; --关闭游标 DEALLOCATE My_Cursor; --释放游标 GO
sql 存储过程里面如何 对数据集循环
A. 在简单的游标中使用 FETCH
以下示例为 Person.Contact 表中姓氏以字母 B 开头的行声明了一个简单的游标,并使用 FETCH NEXT 逐个提取这些行。FETCH 语句以单行结果集形式返回在 DECLARE CURSOR 中指定的列的值。
USE AdventureWorks GO DECLARE contact_cursor CURSOR FOR SELECT LastName FROM Person.Contact WHERE LastName LIKE ‘B%‘ ORDER BY LastName OPEN contact_cursor -- Perform the first fetch. FETCH NEXT FROM contact_cursor -- Check @@FETCH_STATUS to see if there are any more rows to fetch. WHILE @@FETCH_STATUS = 0 BEGIN -- This is executed as long as the previous fetch succeeds. FETCH NEXT FROM contact_cursor END CLOSE contact_cursor DEALLOCATE contact_cursor GO
B. 使用 FETCH 将值存入变量
以下示例与示例 A 相似,但 FETCH 语句的输出存储于局部变量而不是直接返回到客户端。PRINT 语句将变量组合成单一字符串并将其返回到客户端。
USE AdventureWorks GO -- Declare the variables to store the values returned by FETCH. DECLARE @LastName varchar(50), @FirstName varchar(50) DECLARE contact_cursor CURSOR FOR SELECT LastName, FirstName FROM Person.Contact WHERE LastName LIKE ‘B%‘ ORDER BY LastName, FirstName OPEN contact_cursor -- Perform the first fetch and store the values in variables. -- Note: The variables are in the same order as the columns -- in the SELECT statement. FETCH NEXT FROM contact_cursor INTO @LastName, @FirstName -- Check @@FETCH_STATUS to see if there are any more rows to fetch. WHILE @@FETCH_STATUS = 0 BEGIN -- Concatenate and display the current values in the variables. PRINT ‘Contact Name: ‘ + @FirstName + ‘ ‘ + @LastName -- This is executed as long as the previous fetch succeeds. FETCH NEXT FROM contact_cursor INTO @LastName, @FirstName END CLOSE contact_cursor DEALLOCATE contact_cursor GO
标签:
原文地址:http://www.cnblogs.com/UnJie/p/4281595.html