What happened to the *= and =* for outer joins in SQL?

Question

I was just curious as to why the *= operator for left outer join and the '=*' for 'right outer join were taken out of the SQL standard, or, at least not supported by SQL server 2005 and on? I have read a few other posts on this particular operator and understand that it can give some unexpected results. But if it were semantically equivalent I would think it would be an easier operator to use when having to join multiple tables. If anything, I would rather use this operator to to dynamically create sql queries as opposed to trying to get the correct word order like:

FROM accounts 
LEFT OUTER JOIN customers 
ON accounts.accountnum = customers.accountnum 
LEFT OUTER JOIN products 
ON customers.accountnum = products.accountnum 
AND customers.id = products.customerid  

where

FROM accounts, customers, products
WHERE accounts.accountnum *= customers.accountnum AND
      customers.accountnum *= products.accountnum AND
      customers.id *= products.customer.id

would seem to be easier to parse together.

But back to the real world, what was the idea for these operators if they dont perfom a "true" outer join? The term Short Hand implies that it should do exactly the same thing, but obviosly not in this case.

Answer 1

SQL Server MVP K. Brian Kelley does a good job of explaining it here: Why SQL Server 2005 Doesn't Permit Non-ANSI Style OUTER JOINs

Answer 2

I don't think they were taken out of the standard. I think they were never in it. They were just a convention that vendors followed until SQL-92 came out and the vendors decided it was worth implementing.

Answer 3

Do a google search for the Chris Date paper, "Outer Join with No Nulls and Fewer Tears", which pre-dates the SQL-92 Standard. Although I couldn't find a free copy online, I did find a document that analyses the paper and gives a nice potted history of outer join in SQL. Note nowadays Date would relation-valued attributes for this kind of query and would urge you to generally avoid outer joins ;)