Question

我有这个查询正常工作

    UPDATE Master 
    SET Closed = Date(), 
        Status = 'Closed', 
        [Closure Reason] = 'Not on Extract'
    WHERE NOT EXISTS ( SELECT 1
                       FROM Extract
                       WHERE Master.Case = Extract.Case 
                     );

我需要修改它以添加另一个标准，即只有Master的值才会更新。[Closure Reason]为NULL

但这会产生语法错误：

UPDATE Master SET Closed = Date(), Status = 'Closed', [Closure Reason] = 'Not on Extract'
WHERE [Closure Reason] = "" AND
WHERE NOT EXISTS (SELECT 1
                  FROM Extract
                  WHERE Master.Case = Extract.Case
                 );

我尝试使用IS NULL而不是=“”无效。

请问有什么问题？

Answer 1

UPDATE Master SET Closed = Date(), Status = 'Closed', [Closure Reason] = 'Not on Extract'
WHERE [Closure Reason] IS NULL 
AND NOT EXISTS (SELECT 1
                  FROM Extract
                  WHERE Master.Case = Extract.Case
                 );

您无法添加多个WHERE子句，您需要使用AND。如果您的要求是＆＃34;只有在Master。[Closure Reason]的值为NULL＆＃34;时才进行更新，然后检查NULL，而不是空字符串。

Answer 2

您需要在where之前删除第二个not exists。

UPDATE Master SET Closed = Date(), Status = 'Closed', [Closure Reason] = 'Not on Extract'
WHERE [Closure Reason] = "" AND
 NOT EXISTS (SELECT 1
                  FROM Extract
                  WHERE Master.Case = Extract.Case
                 );

Answer 3

您需要添加AND条件运算符，而不是像

那样有两个WHERE子句

WHERE NOT EXISTS (SELECT 1
                  FROM Extract
                  WHERE Master.Case = Extract.Case
                 )
AND [Closure Reason] IS NULL;

如果Field为NULL，则仅更新表

3 个答案: