Modify table: How to change 'Allow Nulls' attribute from not null to allow null

Question

How to change one attribute in a table using T-SQL to allow nulls (not null --> null)? Alter table maybe?

Answer 1

ALTER TABLE public.contract_termination_requests
ALTER COLUMN management_company_id DROP NOT NULL;

Answer 2

This is the approach to do this: -

1. Check whether the table or column exists or not.
2. If yes, then alter the column. e.g:-

IF EXISTS (SELECT 1 FROM INFORMATION_SCHEMA.COLUMNS WHERE 
            TABLE_CATALOG = 'DBName' AND 
            TABLE_SCHEMA = 'SchemaName' AND
            TABLE_NAME = 'TableName' AND
            COLUMN_NAME = 'ColumnName')
BEGIN
    ALTER TABLE DBName.SchemaName.TableName ALTER COLUMN ColumnName [data type] NULL
END  

If you don't have any schema then delete the schema line because you don't need to give the default schema.