Tsql 我可以在一个封闭的窗口中使用NULL吗？

如何将空字符串和null添加到括号中的值列表中。我认为对于空的只是添加“”，但是对于空的，我不太确定

UPDATE ProjectsActiveNotes
SET    NoteTypeID = 1
      ,NoteType = 'USER - CLIENT'
WHERE  NoteCategory = 'Client' AND
       NoteSubCategory IN
       (
        ''
        ,'Delivery'
        ,'Estimate'
        ,'Invoicing'
        ,'Placement'       
       )
GO

感谢您的帮助

您不能在中使用NULL，但可以将其添加到WHERE子句中

UPDATE ProjectsActiveNotes
SET    NoteTypeID = 1
      ,NoteType = 'USER - CLIENT'
WHERE  NoteCategory = 'Client' AND
       (NoteSubCategory IN
       (
        ''
        ,'Delivery'
        ,'Estimate'
        ,'Invoicing'
        ,'Placement'       
       ) or NoteSubCategory is null)
GO    

在中不能使用NULL，但可以将其添加到WHERE子句中

UPDATE ProjectsActiveNotes
SET    NoteTypeID = 1
      ,NoteType = 'USER - CLIENT'
WHERE  NoteCategory = 'Client' AND
       (NoteSubCategory IN
       (
        ''
        ,'Delivery'
        ,'Estimate'
        ,'Invoicing'
        ,'Placement'       
       ) or NoteSubCategory is null)
GO    

用这个

UPDATE  ProjectsActiveNotes
SET     NoteTypeID = 1 ,
        NoteType = 'USER - CLIENT'
WHERE   NoteCategory = 'Client'
        AND COALESCE(NoteSubCategory, '') IN ( '', 'Delivery', 'Estimate',
                                               'Invoicing', 'Placement' )

用这个

UPDATE  ProjectsActiveNotes
SET     NoteTypeID = 1 ,
        NoteType = 'USER - CLIENT'
WHERE   NoteCategory = 'Client'
        AND COALESCE(NoteSubCategory, '') IN ( '', 'Delivery', 'Estimate',
                                               'Invoicing', 'Placement' )

---

另一种方法是使用

ISNULL

：

UPDATE ProjectsActiveNotes
SET    NoteTypeID = 1
      ,NoteType = 'USER - CLIENT'
WHERE  NoteCategory = 'Client' AND
       ISNULL(NoteSubCategory,'') IN
       (
        ''
        ,'Delivery'
        ,'Estimate'
        ,'Invoicing'
        ,'Placement'       
       )
GO

---

另一种方法是使用

ISNULL

：

UPDATE ProjectsActiveNotes
SET    NoteTypeID = 1
      ,NoteType = 'USER - CLIENT'
WHERE  NoteCategory = 'Client' AND
       ISNULL(NoteSubCategory,'') IN
       (
        ''
        ,'Delivery'
        ,'Estimate'
        ,'Invoicing'
        ,'Placement'       
       )
GO