Assuming the column is set to support NULL as a value:
UPDATE YOUR_TABLE
SET column = NULL
Be aware of the database NULL handling - by default in SQL Server, NULL is an INT. So if the column is a different data type you need to CAST/CONVERT NULL to the proper data type:
UPDATE YOUR_TABLE
SET column = CAST(NULL AS DATETIME)
...assuming column is a DATETIME data type in the example above.
Assuming the column is set to support NULL as a value:
UPDATE YOUR_TABLE
SET column = NULL
Be aware of the database NULL handling - by default in SQL Server, NULL is an INT. So if the column is a different data type you need to CAST/CONVERT NULL to the proper data type:
UPDATE YOUR_TABLE
SET column = CAST(NULL AS DATETIME)
...assuming column is a DATETIME data type in the example above.
By using NULL without any quotes.
UPDATE `tablename` SET `fieldName` = NULL;
Default NULL for INT data types - SQL Server Forums
SQL Change null values for integer column โ SQLServerCentral Forums
How to replace a null int with a string
Don't mix data types
Bad form. The UI should take the null and display N/A
If you really want to
Case when col_name is null then 'N/A'
But dont
Please
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