Question

I’m sure the solution is simple, but it evades me.

A table is configured like so:

TABLE NAME = sales
Field 1 = id INT Auto Increment Primary Key
Field 2 = user_id INT NOT NULL
Field 3 = item VARCHAR(100) NOT NULL

So let’s say I’m looking for users that have purchased the following items:

• ipod
• shoes
• bicycle

How would I structure a SQL statement to return the user_id values of users who have purchased the each of the three items (the user must have purchased all three items)?

Answer 1

Join up views of the table for each item

Needs distinct as a user could buy many of one item.

select distinct(ipod.user_id )
from sales ipod
    inner join sales shoes on shoes.user_id = ipod.user_id 
    inner join sales bike on bike.user_id = ipod.user_id 
where ipod.item  = 'ipod' 
    and shoes.item = 'shoes'
    and bike.item = 'bicycle'