All parent table rows left jon child table directly - sql

Question

I have three tables: patron, patron_address, and patron_phone
for every patron/
Patron has 1-3 Patron_address rows
patron_address has 0-4
I want to display all the rows from the patron table and all the phone numbers of phone_type = '4'.
However, when I use the query below, I only get rows that have a phone{type of 4, not all the patron rows.
I tried to get Access 2007 query designer to do this, but something is off-kilter. Patron_address rows have an address_type. Only patron_address rows with address_type 1 have a child phone record.
So how do I get all the patron rows regardless of whether they have a patron_phone of phone_type 1?
SELECT
PATRON.patron_id, PATRON_PHONE.PHONE_TYPE,
PATRON_PHONE.PHONE_NUMBER, PATRON_ADDRESS.ADDRESS_TYPE
FROM
(PATRON
INNER JOIN
PATRON_ADDRESS ON PATRON.PATRON_ID = PATRON_ADDRESS.PATRON_ID)
LEFT JOIN
PATRON_PHONE ON PATRON_ADDRESS.ADDRESS_ID = PATRON_PHONE.ADDRESS_ID
WHERE
(((PATRON_PHONE.PHONE_TYPE) = '4'))
ORDER BY
PATRON.patron_id;
If I add the criterion that the address type must equal 1, I get absolutely nothing back, even though this combination exists in the database. Isn't the behavior I want the point of a left outer join? Thanks.

Answer 1

You have an INNER JOIN from the Patron table to Patron_Addr. This means that there must be matching records in both tables (by PATRON_ID) to return a value.
SELECT PATRON.patron_id, PATRON_PHONE.PHONE_TYPE, PATRON_PHONE.PHONE_NUMBER, PATRON_ADDRESS.ADDRESS_TYPE
FROM PATRON
INNER JOIN PATRON_ADDRESS ON PATRON.PATRON_ID = PATRON_ADDRESS.PATRON_ID
LEFT JOIN PATRON_PHONE ON PATRON_ADDRESS.ADDRESS_ID = PATRON_PHONE.ADDRESS_ID
WHERE PATRON_PHONE.PHONE_TYPE = 4
ORDER BY PATRON.patron_id
You have a LEFT JOIN from address to table so there doesn't need to be a matching phone number.
Since you are filtering for a Phone Type of 4, it will ONLY allow records that do have a phone record where the PHONE_TYPE = 4.
Is your Phone Type field a number or text? SQL Server will try to convert them back and forth but others may not and give an error or just not match - I don't remember how Access might handle this situation.
If you remove the PHONE TYPE criteria, your address criteria should work.
If you want to get all records of parton with address 1 but only phone numbers that are TYPE = 4, change the WHERE PHONE_TYPE=4 to part of the LEFT JOIN:
SELECT PATRON.patron_id, PATRON_PHONE.PHONE_TYPE, PATRON_PHONE.PHONE_NUMBER, PATRON_ADDRESS.ADDRESS_TYPE
FROM PATRON
INNER JOIN PATRON_ADDRESS ON PATRON.PATRON_ID = PATRON_ADDRESS.PATRON_ID
LEFT JOIN PATRON_PHONE ON PATRON_ADDRESS.ADDRESS_ID = PATRON_PHONE.ADDRESS_ID AND PATRON_PHONE.PHONE_TYPE = 4
WHERE PATRON_PHONE.ADDRESS_TYPE = 1
ORDER BY PATRON.patron_id
Access SQL:
SELECT PATRON.patron_id, P_PHONE.PHONE_TYPE, P_PHONE.PHONE_NUMBER, PATRON_ADDRESS.ADDRESS_TYPE
FROM PATRON
INNER JOIN PATRON_ADDRESS ON PATRON.PATRON_ID = PATRON_ADDRESS.PATRON_ID
LEFT JOIN [SELECT * FROM PATRON_PHONE WHERE PATRON_PHONE.PHONE_TYPE = 4 ]. AS P_PHONE ON PATRON_ADDRESS.ADDRESS_ID = P_PHONE.ADDRESS_ID
WHERE PATRON_PHONE.ADDRESS_TYPE = 1
ORDER BY PATRON.patron_id
Access has some goofy syntax for subqueries. You could create a separate query for the P_Phone subquery instead but the results would (should?) be the same.