two statments - same result ????

[Syl]

Hello! Can someone verify this for me please.

Should these 2 statments return the same result ? The 2nd one is the
original, the first one is my re-write. Thanks :

SELECT orders_status, paypalipn_txn . *
FROM orders
INNER JOIN paypalipn_txn ON item_number = orders_id
WHERE customers_id = 4417
ORDER BY date_purchased DESC LIMIT 1

and :

SELECT o.orders_status ,p.*
FROM orders o
LEFT JOIN paypalipn_txn p on p.item_number = o.orders_id
AND o.customers_id = 4417 order by o.date_purchase d desc limit 1

[petersprc]

Re: two statments - same result ????

It doesn't appear to be the same...

The INNER JOIN will return only orders that have a corresponding
paypalipn_txn record and belong to customer 4417.

The original LEFT JOIN returns all orders that belong to customer 4417.
If there's a paypalipn_txn record matching the join criteria, those
fields will be filled in, otherwise they will appear as NULL.

Some more info:

http://download-uk.oracle.com/docs/cd/B10501_01/server.920/a96540/queries7.htm#2054014

http://dev.mysql.com/doc/refman/5.0/en/join.html

Syl wrote:

Hello! Can someone verify this for me please.
>
Should these 2 statments return the same result ? The 2nd one is the
original, the first one is my re-write. Thanks :
>
SELECT orders_status, paypalipn_txn . *
FROM orders
INNER JOIN paypalipn_txn ON item_number = orders_id
WHERE customers_id = 4417
ORDER BY date_purchased DESC LIMIT 1
>
and :
>
SELECT o.orders_status ,p.*
FROM orders o
LEFT JOIN paypalipn_txn p on p.item_number = o.orders_id
AND o.customers_id = 4417 order by o.date_purchase d desc limit 1