A third party application we use generates SQL queries. Here is query it generated that broke today and for which I have a hard time arguing that the postgres behavior is correct (minimally the error message is confusing):
=# create temporary table foo (b double precision ); CREATE TABLE Time: 40.368 ms =# insert into foo select min(NULL); ERROR: column "b" is of type double precision but expression is of type text LINE 1: insert into foo select min(NULL); ^ HINT: You will need to rewrite or cast the expression.
So why does min(NULL) have type text? According to the docs it has the type of the input. The value is itself NULL which is a valid member of all types in SQL isn't it?
From:
Amit kapila Date: Subject:
Re: ALTER SYSTEM SET command to change postgresql.conf parameters
(RE: Proposal for Allow postgresql.conf values to be changed via
SQL [review])