Let's say there's a table created as follows:
create table testTable ( colA int not null )
How would you drop the not null constraint? I'm looking for something along the lines of
ALTER TABLE testTable ALTER COLUMN colA DROP NOT NULL;
which is what it would look like if I used PostgreSQL. To my amazement, as far as I've been able to find, the MySQL docs, Google and yes, even Stackoverflow (in spite of dozens or hundreds of NULL-related questions) don't seem to lead towards a single simple SQL statement which will do the job.
Removing a NOT NULL constraint is pretty easy, no matter the constraint name was provided by system or user, you can just declare the column as NULL at attribute-level to revert the constraint. SQL> alter table countries modify (region_id null); Table altered.
To remove a NOT NULL constraint for a column in Snowflake, you use the ALTER TABLE <table_name> ALTER <column_name> DROP command and restate the column definition, adding the NOT NULL attribute.
By default, a column can hold NULL values. The NOT NULL constraint enforces a column to NOT accept NULL values. This enforces a field to always contain a value, which means that you cannot insert a new record, or update a record without adding a value to this field.
I would try something like this
ALTER TABLE testTable MODIFY COLUMN colA int;
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