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Thread: Working on "SELECT * WHERE numeric_col = 2001.2" problem?

Working on "SELECT * WHERE numeric_col = 2001.2" problem?

From
"Bob Jones"
Date:

Over the past year I have been using MySQL to serve as the backend for our WIN32 ODBC client. After reading several articles regarding PostgreSQL, I decided to give it a try, hoping that by moving our data over to pgsql I could gain some additional features (primarily COMMIT and ROLLBACK)... Converting the WIN32 client has gone fairly well with the exception of one, perhaps two problems.

First of all, here's a brief breakdown of the box I'm running the SQL server on:
i686 Machine
RH Linux 7.0   2.2.16-22
PostgreSQL v7.1.3

There are times where the client makes queries to the server to the effect of:
"SELECT * FROM cyear WHERE year=2001.5"

 

but is given an error stating that the '=' operator is unidentified for numeric and float8 types.

After receiving this error, I checked the doc/TODO file and found that the deficiency was known...\

Is this an issue that is to be addressed in later (hopefully in the near future?) revisions of pgsql, or is it a relatively low priority?

This feature is absolutely critical for the functionality of our program; if a reasonable workaround/fix isn't available I'll have to continue with MySQL.

Thanks,
Bob

Re: Working on "SELECT * WHERE numeric_col = 2001.2" problem?

From
Tom Lane
Date:
"Bob Jones" <bjones@autoresourcesinc.com> writes:
> ... an error stating that the '=' operator is unidentified for
> numeric and float8 types.
> After receiving this error, I checked the doc/TODO file and found that
> the deficiency was known...\
> Is this an issue that is to be addressed in later (hopefully in the near
> future?) revisions of pgsql, or is it a relatively low priority?

It's not so much that it's low priority as that a non-hack solution
requires some rather subtle revisions of Postgres' type system, and
there's not yet agreement on how to do that.  (Look through the
pghackers list archives if you want to see the previous discussions.)

Quick-hack solutions include (a) persuading your client program to
put single-quotes around the literal, or (b) defining your own
numeric-vs-float8-equals operator.  AFAIK (b) would not support the
use of indexes on the numeric column, so it's not a very good solution,
but it might do as a stopgap.

            regards, tom lane