Re: BUG #14693: create materialized view forces btrim

Thanks very much folks. For your entertainment, this seems to be working. I
changed the expression to trim(from foo) || bar, in my select statement,
and reliably got a non-empty result. I committed this via "create
materialized view", and inspected what Postgres did with it (\dSm+). It
*still* is stored as btrim(foo) || bar; and yet, it works correctly(?!)

On Tue, Jun 6, 2017 at 4:51 PM, David G. Johnston <
david(dot)g(dot)johnston(at)gmail(dot)com> wrote:

> On Tue, Jun 6, 2017 at 1:25 PM, <isb0459(at)gmail(dot)com> wrote:
>
>> I am trying to create a materialized view. I have a working SQL query that
>> uses this expression: coalesce(trim(foo), bar). When I use that in the
>> definition for create materialized view, Postgres force replaces the
>> trim()
>> call into a btrim() and breaks the query result. In my specific case, all
>> the values become empty instead of yielding either the trimmed "foo" or
>> the
>> "bar" fields if trimmed "foo" is empty. Is there a way to make Postgres
>> use
>> the function trim as I require?
>>
>
> ​COALESCE returns the first non-null value. The empty string is non-null
> and so it will be returned.
>
> try:
>
> COALESCE(NULLIF(trim(foo), ''), bar);
>
> David J.
> ​
>