Question

I am creating a personnel database and have multiple tables relating to a user that include things like medical examinations, passports, vaccinations, memberships etc.

Each of these tables contains an expiry record which I want to query all tables on. Basically I want to have a list of items that are going to expire in a certain time, something like:

John - Passport expires in 1 month
Emma - Vaccination expires in 1 month
Carol - Vaccination expires in 3 weeks
Josh - Medical expires in 2 weeks
James - Passport expires in 3 days

What is the best way to do this, can it somehow be done in a single query?

Thanks in advance

Answer 1

It could be done in a single query using union:

(SELECT name, 'passport', expiry_date FROM table_passport WHERE ...) 
UNION ALL 
(SELECT name, 'vaccination', expiry_date FROM table_vaccinations WHERE ...) 
UNION ALL 
(SELECT name, 'medical', expiry_date FROM table_medical WHERE ...) 
ORDER BY name;