问题
How do I clear the value from a cell and make it NULL?
回答1:
I think @Zack properly answered the question but just to cover all the bases:
Update myTable set MyColumn = NULL
This would set the entire column to null as the Question Title asks.
To set a specific row on a specific column to null use:
Update myTable set MyColumn = NULL where Field = Condition.
This would set a specific cell to null as the inner question asks.
回答2:
If you've opened a table and you want to clear an existing value to NULL, click on the value, and press Ctrl+0.
回答3:
If you are using the table interface you can type in NULL (all caps)
otherwise you can run an update statement where you could:
Update table set ColumnName = NULL where [Filter for record here]
回答4:
Use This:
Update Table Set Column = CAST(NULL As Column Type) where Condition
Like This:
Update News Set Title = CAST(NULL As nvarchar(100)) Where ID = 50
回答5:
Ctrl+0 or empty the value and hit enter.
来源：https://stackoverflow.com/questions/444657/how-do-i-set-a-column-value-to-null-in-sql-server-management-studio