Postgres Support Task Force

I've taken it upon myself to help add PostgreSQL support to any contrib modules that I spend time working with and it's clear that many people have no experience with how to handle the differences in table definitions and compatible/incompatible queries.

Consider me on board to help out with this cause!

The latest PostgreSQL release 8.3 includes a new change in behaviour from previous versions regarding JOINS on columns that are not the same data type. See http://www.postgresql.org/docs/8.3/static/release-8-3.html

This issue has already been reported in the following Drupal issues:

http://drupal.org/node/220064
http://drupal.org/node/226503
http://drupal.org/node/229051

Non-character data types are no longer automatically cast to TEXT (Peter, Tom)

Previously, if a non-character value was supplied to an operator or function that requires text input, it was automatically cast to text, for most (though not all) built-in data types. This no longer happens: an explicit cast to text is now required for all non-character-string types. For example, these expressions formerly worked:

substr(current_date, 1, 4)
23 LIKE '2%'

but will now draw "function does not exist" and "operator does not exist" errors respectively. Use an explicit cast instead:

substr(current_date::text, 1, 4)
23::text LIKE '2%'

(Of course, you can use the more verbose CAST() syntax too.) The reason for the change is that these automatic casts too often caused surprising behavior. An example is that in previous releases, this expression was accepted but did not do what was expected:

current_date < 2017-11-17

This is actually comparing a date to an integer, which should be (and now is) rejected — but in the presence of automatic casts both sides were cast to text and a textual comparison was done, because the text < text operator was able to match the expression when no other < operator could.

Types char(n) and varchar(n) still cast to text automatically. Also, automatic casting to text still works for inputs to the concatenation (||) operator, so long as least one input is a character-string type.