FETCH未完成空白

Question

我遇到问题FETCH我正在使用它：

DECLARE Something CURSOR FOR  
SELECT * FROM tblSomething

OPEN Something

WHILE @@FETCH_STATUS = 0
    BEGIN   
        --CALL ANOTHER PROCEDURE
        FETCH NEXT FROM Something
    END 
CLOSE Something
DEALLOCATE Something

问题是表中有10行，11行出来，第11行是空白数据。我认为这是获取下一行并意识到没有下一行。我需要某种形式：

IF FETCH_ROWS = MAX then STOP

或类似的东西。

Answer 1

尝试在FETCH NEXT FROM和OPEN之间添加WHILE：

DECLARE Something CURSOR FOR  
SELECT * FROM tblSomething

OPEN Something
FETCH NEXT FROM Something   --  <== add this line
WHILE @@FETCH_STATUS = 0
    BEGIN   
        --CALL ANOTHER PROCEDURE
        FETCH NEXT FROM Something
    END 
CLOSE Something
DEALLOCATE Something

这是一个简单的演示，包含一个10行的表和一个读取每一行并打印相应ID的游标：

declare @tmp table (row_id int)
insert into @tmp values (1), (2), (3), (4), (5), (6), (7), (8), (9), (10) 

DECLARE @myID as int;
DECLARE @wf_Cursor as CURSOR;
SET @wf_Cursor = CURSOR FOR SELECT row_id FROM @tmp

OPEN @wf_Cursor;
    FETCH NEXT FROM @wf_Cursor INTO @myID;
    WHILE @@FETCH_STATUS = 0
        BEGIN
            print('Reading row: ' + cast(@myID as nvarchar(10)));
            FETCH NEXT FROM @wf_Cursor INTO @myID;
        END
CLOSE @wf_Cursor;
DEALLOCATE @wf_Cursor;

输出：