Question

SELECT * 

FROM 
    daaddress ad, 
    (daname nam LEFT OUTER JOIN daenttonam etn on nam.entity_id = etn.entity_id) 

I don’t understand what the two “tables” seperated by a comma with no JOIN statement is supposed to do. Is it a FULL?

Answer 1

It outputs the cartesian product between daadress and a LEFT JOIN of daname and daenttonam.

Using JOIN syntax, it can be rewritten as:

SELECT  * 
FROM   daaddress ad
CROSS JOIN
(
       daname nam
LEFT OUTER JOIN
       daenttonam etn
ON     nam.entity_id = etn.entity_id
) 

The parens may be omitted:

SELECT  * 
FROM   daaddress ad
CROSS JOIN
       daname nam
LEFT OUTER JOIN
       daenttonam etn
ON     nam.entity_id = etn.entity_id

It’s hard to tell its purpose not being aware of the model specifics.