How to add not null constraint to existing column in MySQL

June 2, 2022 by IT Nursery

I have table name called “Person” with following column names

P_Id(int),
LastName(varchar),
FirstName (varchar).

I forgot to give NOT NULL Constraint to P_Id.

Now I tried with following query to add NOT NULL Constraint to existing column called P_Id,

1. ALTER TABLE  Person MODIFY  (P_Id NOT  NULL);
2. ALTER TABLE Person ADD CONSTRAINT NOT  NULL NOT NULL (P_Id);

I am getting syntax error….

3 Answers
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