From: pgsql-general-ow...@postgresql.org [mailto:pgsql-general-ow...@postgresql.org] On Behalf Of salah jubeh Sent: Wednesday, December 21, 2011 6:39 AM To: pgsql Subject: [GENERAL] can not use the column after rename
Hello, Why I can not do something like this in Postgres. SELECT 1 as a , 2 as b , a + b as c ; Regards In a declarative language same-level cross-references are difficult to process (though admittedly not impossible). What if you had written: SELECT a + b AS c, 1 as a, 2 as b If scanned in a linear (top-to-bottom) fashion A and B would not be defined at the time the "a + b" part was evaluated. David J.
