sql-server - SQL Server 2008 中的 Do while 循环

Question

SQL Server 2008中有没有实现do while循环的方法？

Answer 1

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/

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
   

但请尝试在数据库级别避免循环。 Reference .