MySQL show all columns while using WHERE clause - mysql

Question

Sorry if this is a silly question but did not use much SQL lately and can't find much help on this either.
I need to get all rows to show in a result even if the result is 0 or null. The problem I have is because of the WHERE clause (without the WHERE the rows are all displayed but the data is not).
SELECT SUM(c.amount) AS 'total_income', p.ref_id AS 'property'
FROM property p
LEFT JOIN contract c
ON p.id = c.property_ref_id
LEFT JOIN contract_payment cp
ON c.id = cp.contract_id
WHERE cp.paid = 1 AND year(cp.date_paid) = :year
GROUP BY p.id
Displaying the result set without the Where and Bad Data would be like this
array
0 =>
array
'total_income' => null
'property' => string 'test/0001' (length=9)
1 =>
array
'total_income' => null
'property' => string 'test/0002' (length=9)
2 =>
array
'total_income' => string '200' (length=3)
'property' => string 'test/0003' (length=9)
3 =>
array
'total_income' => string '16100' (length=5)
'property' => string 'test/0004' (length=9)
While this is the result set with the WHERE clause and Good Data but not all rows
array
0 =>
array
'total_income' => string '4200' (length=4)
'property' => string 'test/0004' (length=9)
Could someone please enlighten me to what modifications could be made to the SQL so as to retrieve my desired data ?

Answer 1

The problem is that you're filtering out all the rows with no match in the cp table, because cp.paid can't be 1 when there's no match there.
Change the WHERE clause to:
WHERE cp.contract_id IS NULL OR (cp.paid = 1 AND year(cp.date_paid) = :year)
or move that condition into the ON clause of the LEFT JOIN with cp:
ON c.id = cp.contract_id AND cp.paid = 1 AND year(cp.date_paid) = :year