如何在while循环中手动中断光标？

Posted 2023-03-15

【中文标题】如何在while循环中手动中断光标？

【英文标题】：How to manually break the cursor within a while loop?

【发布时间】：2015-04-06 06:24:49

【问题描述】：

如果while循环命中break命令退出循环，如果光标命中break命令，如何完全退出while循环？

例如：

DECLARE @CursorTest TABLE 
(
    idcol INT ,
    fld1 INT,
    fld2 INT,
    fld3 CHAR(800)
)

INSERT INTO @CursorTest (fld1, fld2, fld3)

SELECT 1, RAND() * 100 * DATEPART(ms, GETDATE()), LEFT(REPLICATE(CAST(NEWID() AS VARCHAR(36)),30),800)


DECLARE @Variable1 INT, @Variable2 INT
DECLARE CursorName CURSOR FAST_FORWARD
FOR
SELECT idcol    FROM @CursorTest    
OPEN CursorName
FETCH NEXT FROM CursorName  INTO @Variable1
WHILE @@FETCH_STATUS = 0
BEGIN   
    if (@Variable1 =10) 
    BEGIN
        BREAK
    END 
    PRINT CAST(@Variable1 AS VARCHAR(5))

FETCH NEXT FROM CursorName  INTO @Variable1
 
END
CLOSE CursorName
DEALLOCATE CursorName

【参考方案1】：

您可以在WHILE 循环中给出一些在光标上迭代的条件。第一个条件是@@FETCH_STATUS，其他条件是你想打破循环

WHILE @@FETCH_STATUS = 0 OR @stopLoop = false
   BEGIN
      FETCH NEXT FROM Employee_Cursor;
      //your code
      if condition 
      BEGIN
          @stopLoop = true
      END 
   END;
CLOSE Employee_Cursor;

使用 BREAK 语句

WHILE @@FETCH_STATUS = 0 
   BEGIN
      FETCH NEXT FROM Employee_Cursor;
      //your code
      if condition 
      BEGIN
          BREAK
      END 
   END;
CLOSE Employee_Cursor;

【讨论】：

不会是 WHILE @@FETCH_STATUS = 0 AND @stopLoop = false 而不是 OR ？