Avoid inserting a particular value into sql table

Question

I am not sure, if this can be achieved in SQL.

INSERT INTO table_name (column1, column2, column3) 
VALUES (value1, value2, 999);

If the user tries to insert 999 in column3, convert it to null or avoid inserting it.

I am trying to find if I can find any solution from SQL Server side.

Answer 1

How about using a Check Constraint:

ALTER TABLE table_name
ADD CHECK (column3<>999);