mysql search 2 tables with overlap - php

Question

i have 2 tables, see below - profiles is my main/master table
profiles invoices
____________ ___________________
|id Name | |profileid paid |
|============| |===================|
|1 Abraham | | 2 unpaid |
|2 Martin | | 3 unpaid |
|3 John | | 3 paid |
|____________| |___________________|
as can be seen, abraham has 0 invoices, martin has 1 unpaid invoice, and john has 2 invoices; 1 paid, 1 unpaid.
i want to search for:
all profiles with paid invoices (john)
all profiles with unpaid invoices (john & martin)
all profiles with both paid AND unpaid invoice(s) (john)
i can do 1 and 2 fine but im having a problem with step 3.
here is my query for 1;
$query = "SELECT DISTINCT profiles.name
FROM profiles LEFT JOIN invoices ON (profiles.id=invoices.profileid)
AND (invoices.paid='paid' OR invoices.paid='unpaid')
WHERE
IFNULL(invoices.paid, '') LIKE 'paid';
here is my query for 2;
$query = "SELECT DISTINCT profiles.name
FROM profiles LEFT JOIN invoices ON (profiles.id=invoices.profileid)
AND (invoices.paid='paid' OR invoices.paid='unpaid')
WHERE
IFNULL(invoices.paid, '') LIKE 'unpaid';
here is my query for 3;
$query = "SELECT DISTINCT profiles.name
FROM profiles LEFT JOIN invoices ON (profiles.id=invoices.profileid)
AND (invoices.paid='paid' OR invoices.paid='unpaid')
WHERE
IFNULL(invoices.paid, '') LIKE 'paid'
AND IFNULL(invoices.paid, '') LIKE 'unpaid'
;
as mentioned, 1 & 2 work fine, but 3 gives me 0 results.
any help is much appreciated. thanks

Answer 1

You need to select the invoices table 2 times, in order to get where someone has both paid and unpaid. Try something like -
SELECT DISTINCT profiles.name
FROM profiles
LEFT JOIN invoices i1 ON (profiles.id=i1.profileid)
AND (i1.paid='paid')
LEFT JOIN invoices i2 ON (profiles.id=i2.profileid)
AND (i2.paid='unpaid')
WHERE
IFNULL(i1.paid, '') LIKE 'paid'
AND IFNULL(i2.paid, '') LIKE 'unpaid';
see this sqlfiddle example - http://sqlfiddle.com/#!2/ee4e2/4

Answer 2

One possibility is a sub query to count the distinct invoice types associated with a profile
SELECT `profiles`.`name`
FROM `profiles`
WHERE (
SELECT count( DISTINCT `subinvoices`.`paid` )
FROM `invoices` AS `subinvoices`
WHERE `profiles`.`id` = `subinvoices`.`profileid`
AND (`subinvoices`.`paid` = 'paid' OR `subinvoices`.`paid` = 'unpaid')
) = 2

Answer 3

The easiest way to do this is with aggregation:
select p.*, coalesce(InvoiceInfo, 'NONE')
from profiles p left outer join
(select profileid,
(case when sum(paid = 'PAID') > 0 and sum(paid = 'UNPAID') > 0 then 'BOTH'
when sum(paid = 'PAID') > 0 then 'PAID-ONLY'
when sum(paid = 'UNPAID') > 0 then 'UNPAID-ONLY'
end) as InvoiceInfo
from invoices i
)
on p.id = i.profileid
This allows you to get all three types of information at once. You can count the people in each group, for instance, by doing:
select coalesce(InvoiceInfo, 'NONE'), count(*)
from profiles p left outer join
(select profileid,
(case when sum(paid = 'PAID') > 0 and sum(paid = 'UNPAID') > 0 then 'BOTH'
when sum(paid = 'PAID') > 0 then 'PAID-ONLY'
when sum(paid = 'UNPAID') > 0 then 'UNPAID-ONLY'
end) as InvoiceInfo
from invoices i
)
on p.id = i.profileid
group by coalesce(InvoiceInfo, 'NONE')