Join one row to multiple rows in another table

Question

I have a table to entities (lets call them people) and properties (one person can have an arbitrary number of properties). Ex:

People

Name  Age
---         


        

Answer 1

You can use INNER JOIN to link the two tables together. More info on JOINs.

SELECT *
FROM People P
INNER JOIN Properties Pr
  ON Pr.Name = P.Name
WHERE P.Name = 'Joe' -- or a specific age, etc

However, it's often a lot faster to add a unique primary key to tables like these, and to create an index to increase speed.

Say the table People has a field id
And the table Properties has a field peopleId to link them together

Then the query would then look something like this:

SELECT *
FROM People P
INNER JOIN Properties Pr
  ON Pr.id = P.peopleId
WHERE P.Name = 'Joe'