当@@ ROWCOUNT = 0时,TSQL中断循环

Question

我在SPROC中插入语句(简化),如下所示

SET ROWCOUNT 100

WHILE(1=1)
BEGIN

  INSERT INTO table1
  SELECT *
  FROM table2
  WHERE some_condition
  -- EDIT: Realized forgot to include this following vital line that is causing issue
  SET @var = @var + @@ROWCOUNT    

  -- @@ROWCOUNT now takes on a value of 1, which will cause the following IF check to fail even when no lines are inserted

  IF(@@ROWCOUNT = 0)
  BEGIN
    BREAK
  END

END

但问题是,在任何操作之后,即使没有更多的行适合我some_condition,@@ROWCOUNT也等于1,而不是0.

当有0行返回匹配我时,如何打破该循环some_condition？

Answer 1

"set"语句创建的行数为1.您应该立即将@@ ROWCOUNT保存到@rowCount变量中并稍后使用该var.

declare @rowCount int

WHILE(1=1)
BEGIN

  INSERT INTO table1
  SELECT *
  FROM table2
  WHERE some_condition
  -- EDIT: Realized forgot to include this following vital line that is causing issue
  SET @rowCount = @@ROWCOUNT
  SET @var = @var + @rowCount    

  -- @@ROWCOUNT now takes on a value of 1, which will cause the following IF check to fail even when no lines are inserted

  IF(@rowCount = 0)
  BEGIN
    BREAK
  END

END

此外,您可以通过将@rowCount初始设置为-1并将WHILE条件更改为@rowCount <> 0来简化.将不再需要条件BREAK.