如何使用SQL中的“With”子句更新值

Posted 2021-04-14

我想根据'With'子句中的结果更新表的列。当我在update语句中使用tb时，它显示无效的对象名称，因为它已经在'With'子句中。如果有人可以帮我这个。谢谢！

;WITH Split_Segments AS 
(
    SELECT 
        W.ROW_ID
    FROM 
        table1 W
    WHERE
        W.ERRORS IS NULL AND W.UserName = @userId
),
tb AS 
(
    SELECT DISTINCT
        ROW_ID, AP
    FROM 
        Split_Segments 
    WHERE 
        LEN(AP) <> 3  
)
SELECT 
    A.ROW_ID
INTO 
    #tempTable
FROM
    Split_Segments  A
INNER JOIN 
    table4 B ON A.ROW_ID = B.ROW_ID
             AND A.AP = B.AP
LEFT OUTER JOIN 
    tb Z ON A.ROW_ID = Z.ROW_ID
WHERE 
    Z.AP IS NULL;

我想运行以下声明：

UPDATE W SET ERRORS = 'Error' 
FROM table5 W
INNER JOIN tb T ON W.ROW_ID = T.ROW_ID
WHERE AP IS NOT NULL;

答案

好的，如果我按照正确的方式行事，那么这就是您要执行的更新，对吧？ UPDATE W SET ERRORS = 'Error' FROM table5 W INNER JOIN tb T ON W.ROW_ID = T.ROW_ID WHERE AP IS NOT NULL;

要做到这一点，你需要tb，这是一个CTE ...所以添加它：

;WITH tb AS ( SELECT DISTINCT ROW_ID, AP FROM Split_Segments WHERE LEN(AP) <> 3
) UPDATE W SET ERRORS = 'Error' FROM table5 W INNER JOIN tb T ON W.ROW_ID = T.ROW_ID WHERE AP IS NOT NULL;

现在tb还需要Split_Segments，这也是一个CTE，因此也需要包含......

;WITH Split_Segments AS ( SELECT W.ROW_ID FROM table1 W WHERE W.ERRORS IS NULL AND W.UserName = @userId ),tb AS ( SELECT DISTINCT ROW_ID, AP FROM Split_Segments WHERE LEN(AP) <> 3
) UPDATE W SET ERRORS = 'Error' FROM table5 W INNER JOIN tb T ON W.ROW_ID = T.ROW_ID WHERE AP IS NOT NULL;

那里......现在它应该工作......更新中没有任何东西需要临时表或除了CTE之外的任何其他东西....

另一答案

你只能在SELECT声明结尾处运行一个UPDATE或WITH。由于您已指定需要访问此CTE子句之外的#tempTable，但该表依赖于tb进行构造，我建议将tb移动到临时表：

Remove tb from within the WITH clause:

 --Provisioning tb as temp table outside of CTE
 SELECT DISTINCT 
   ROW_ID, 
   AP
 INTO tb
 FROM table2
 WHERE LEN(AP) <> 3;

--Provisioning temp table outside of CTE
SELECT A.ROW_ID
INTO #tempTable
FROM table3 A
  INNER JOIN table4 B ON A.ROW_ID = B.ROW_ID
    AND A.AP = B.AP
  LEFT OUTER JOIN tb Z ON A.ROW_ID = Z.ROW_ID
WHERE Z.AP IS NULL;

WITH Split_Segments AS (
    SELECT 
      W.ROW_ID
    FROM 
      table1 W
    WHERE
      W.ERRORS IS NULL AND W.UserName = @userId)

UPDATE W SET ERRORS = 'Error' 
FROM table5 W
  INNER JOIN tb T ON W.ROW_ID = T.ROW_ID
WHERE AP is not null;

编辑：根据表意外情况的数量，为什么不直接使用所有涉及的数据集的临时表？：

SELECT W.ROW_ID
INTO #tempSplit_Segments
FROM table1 W
WHERE W.ERRORS IS NULL AND W.UserName = @userId

SELECT DISTINCT ROW_ID, AP
FROM #tempSplit_Segments 
WHERE LEN(AP) <> 3;

SELECT A.ROW_ID
INTO #tempTable
FROM #tempSplit_Segments A
  INNER JOIN table4 B ON A.ROW_ID = B.ROW_ID
    AND A.AP = B.AP
  LEFT OUTER JOIN tb Z ON A.ROW_ID = Z.ROW_ID
WHERE Z.AP IS NULL;

UPDATE W SET ERRORS = 'Error' 
FROM table5 W
  INNER JOIN tb T ON W.ROW_ID = T.ROW_ID
WHERE AP is not null;