Outer joins

Prior to Genero db version 3.60, the Genero db syntax for OUTER joins is different from the original Informix^® outer join syntax. Genero db version 3.60 supports the same OUTER joins syntax as Informix.

In Informix SQL, outer tables are defined in the FROM clause using the OUTER keyword:

SELECT ... FROM a, OUTER(b)
 WHERE a.key = b.akey

SELECT ... FROM a, OUTER(b,OUTER(c))
 WHERE a.key = b.akey    AND b.key1 = c.bkey1
  AND b.key2 = c.bkey2

Genero db also supports ANSI syntax joins:

SELECT ... FROM a, LEFT OUTER JOIN b ON a.key = b.key

SELECT ... FROM a 
	LEFT OUTER JOIN  b LEFT OUTER JOIN c
	ON ( (b.key1 = c.bkey1) AND (b.key2 = c.bkey2) ) ON ( (a.key = b.akey) )

Solution

Genero db supports Informix outer joins syntax, with the limitation that sub-queries are not allowed in outer-join predicates.

However, for SQL portability, you should use the ANSI outer join syntax instead of the old Informix OUTER syntax.