TSQL中斷循環ROWCOUNT = 0

Question

我有insert語句（簡體）像下面

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 

一個存儲過程，但問題是，任何操作後，即使沒有更多的行適合我some_condition，@@ROWCOUNT等於1，而不是0。

當有0行返回匹配我的some_condition時，我該如何中斷該循環？

Answer 1

實施類似於Moho的解決方案，但使用SELECT而不是SET來存儲@@ROWCOUNT。

Answer 2

另一種解決方案。這將檢查每個迭代以查看最後插入的記錄的ID是否已更改。如果沒有更改，則表示沒有記錄添加該迭代。

SET ROWCOUNT 100 
declare @id int; 
WHILE(1=1) 

    INSERT INTO table1 
    SELECT * 
    FROM table2 
    WHERE some_condition 

    IF(@id= @@identity) 
    BEGIN 
    BREAK 
    END 
    set @id = @@identity; 
END 

Answer 3

試試這個解決方案：

1解決方案

使用@@ROWCOUNT在循環的條件。

SET ROWCOUNT 100 

    INSERT INTO table1 
    SELECT * 
    FROM table2 
    WHERE some_condition 


WHILE(@@ROWCOUNT > 0) 
BEGIN 

    INSERT INTO table1 
    SELECT * 
    FROM table2 
    WHERE some_condition 

END 

第二孤子

使用goto。

SET ROWCOUNT 100 

WHILE(1=1) 
BEGIN 

    INSERT INTO table1 
    SELECT * 
    FROM table2 
    WHERE some_condition 

    IF(@@ROWCOUNT = 0) 
    BEGIN 
    goto label 
    END 

END 

label1: 
print 'After lopp' 

Answer 4

我認爲你應該使用select得到@@rowcount到一個變量。試試這個：

declare @number_of_rows int  

SET ROWCOUNT 100 

WHILE(1=1) 
BEGIN 

    INSERT INTO table1 
    SELECT * 
    FROM table2 
    WHERE some_condition 

    SELECT @number_of_rows=@@ROWCOUNT 

    IF (@number_of_rows = 0) 
    BEGIN 
    BREAK 
    END 
END 

Answer 5

「設置」語句創建爲1的行數，你應該做的是立即@@ ROWCOUNT保存到一個變量@RowCount，後來使用該變種。

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 

另外，還可以通過最初設置@RowCount爲-1​​和改變WHILE條件@RowCount <> 0將不再需要該條件BREAK簡化。