在 SQL Server 2008 中执行 while 循环

SQL server 2008有没有实现do while循环的方法?

解决方案

我不确定 MS SQL Server 2008 中的 DO-WHILE，但您可以更改 WHILE 循环逻辑，以便像 DO-WHILE 循环一样使用.

示例取自此处:http://blog.sqlauthority.com/2007/10/24/sql-server-simple-example-of-while-loop-with-continue-and-break-keywords/

<块引用>

1. WHILE 循环示例

   DECLARE @intFlag INT设置@intFlag = 1同时 (@intFlag <=5)开始打印@intFlagSET @intFlag = @intFlag + 1结尾走

   结果集:

   12345

2. 带有 BREAK 关键字的 WHILE 循环示例

   DECLARE @intFlag INT设置@intFlag = 1同时 (@intFlag <=5)开始打印@intFlagSET @intFlag = @intFlag + 1如果@intFlag = 4休息;结尾走

   结果集:

   123

3. 带有 CONTINUE 和 BREAK 关键字的 WHILE 循环示例

   DECLARE @intFlag INT设置@intFlag = 1同时 (@intFlag <=5)开始打印@intFlagSET @intFlag = @intFlag + 1继续;IF @intFlag = 4 -- 这将永远不会执行休息;结尾走

   结果集:

   12345

但是尽量在数据库级别避免循环.参考.

Is there any method for implement do while loop in SQL server 2008?

解决方案

I am not sure about DO-WHILE IN MS SQL Server 2008 but you can change your WHILE loop logic, so as to USE like DO-WHILE loop.

Examples are taken from here: http://blog.sqlauthority.com/2007/10/24/sql-server-simple-example-of-while-loop-with-continue-and-break-keywords/

1. Example of WHILE Loop

   DECLARE @intFlag INT
   SET @intFlag = 1
   WHILE (@intFlag <=5)
   BEGIN
       PRINT @intFlag
       SET @intFlag = @intFlag + 1
   END
   GO
   

   ResultSet:

   1
   2
   3
   4
   5
   

2. Example of WHILE Loop with BREAK keyword

   DECLARE @intFlag INT
   SET @intFlag = 1
   WHILE (@intFlag <=5)
   BEGIN
       PRINT @intFlag
       SET @intFlag = @intFlag + 1
       IF @intFlag = 4
           BREAK;
   END
   GO
   

   ResultSet:

   1
   2
   3
   

3. Example of WHILE Loop with CONTINUE and BREAK keywords

   DECLARE @intFlag INT
   SET @intFlag = 1
   WHILE (@intFlag <=5)
   BEGIN
       PRINT @intFlag
       SET @intFlag = @intFlag + 1
       CONTINUE;
       IF @intFlag = 4 -- This will never executed
           BREAK;
   END
   GO
   

   ResultSet:

   1
   2
   3
   4
   5
   

But try to avoid loops at database level. Reference.