Re: NULL in arrays

On Sun, Nov 05, 2006 at 09:53:08PM +0100, Martijn van Oosterhout wrote:
> Note that the constructs:
>
> ARRAY['a',"NULL",'c']
>
> and
>
> '{a,"NULL",c}'
>
> are *completely* different. The first is a special array constructor
> and all its parameters are normal SQL expressions, so you can reference
> columns and use NULL directly without quotes. The latter is the string
> value of the array, which is specially decoded. Thats why the latter
> treats the double quotes differently.

This could probably be expanded on in the docs... mentioning the
difference in the NULLs section would be a good start. IE:

To set an element of an array constant to NULL, write NULL for the
element value. (Any upper- or lower-case variant of NULL will do.) If
you want an actual string value "NULL", you must put double quotes
around it. Note that if you use the ARRAY construct you should just use
a bareword NULL instead.
--
Jim Nasby jim(at)nasby(dot)net
EnterpriseDB http://enterprisedb.com 512.569.9461 (cell)