Re: problem porting MySQL SQL to Postgres

On 15/04/2004 11:25 Dan Field wrote:
> I've stumbled across a query I don't quite understand the error message
> for.
>
> This query is pulled from a working MySQL setup:
>
> SELECT
> DEWEY_ID, DEWEY_HUNDREDS, DEWEY_TENS, DEWEY_ONES,
> DEWEY_POINT_ONES, DEWEY_POINT_TENS, DEWEY_POINT_HUNDREDS,
> DEWEY_POINT_THOUSANDS, DEWEY_TYPE, DEWEY_LANG, DEWEY_SUBJECT
> FROM lu_dewey
> WHERE
> (DEWEY_HUNDREDS = 9) AND
> (DEWEY_TENS >= 0) AND (DEWEY_TENS <= 9) AND
> (DEWEY_ONES = 0 || DEWEY_ONES = NULL) AND
> (DEWEY_POINT_ONES = 0 || DEWEY_POINT_ONES = NULL) AND
> (DEWEY_POINT_TENS = 0 || DEWEY_POINT_TENS = NULL) AND
> (DEWEY_POINT_HUNDREDS = 0 || DEWEY_POINT_HUNDREDS = NULL) AND
> (DEWEY_POINT_THOUSANDS = 0 || DEWEY_POINT_THOUSANDS = NULL) AND
> (DEWEY_TYPE = 't') AND
> (DEWEY_LANG = 'en')
> ORDER BY DEWEY_TENS
>
>
> However I'm getting the following error:
>
> ERROR: Unable to identify an operator '=' for types 'character' and
> 'boolean' You will have to retype this query using an explicit cast.
>
>
> Any help would be much appreciated

You're trying to use the string concatenation operator (||) in a boolean
test.. That's an invalid comparison according to the SQL specs. You need
to use the SQL OR operator e.e.,

(DEWEY_POINT_TENS = 0 OR DEWEY_POINT_TENS = NULL) AND
~~

Your "= NULL" tests are also not valid SQL (should be IS NULL). MySQL does
not follow the specs in a number or areas. PostgreSQL is very
standards-complient. Write valid SQL and you should be OK.

HTH

--
Paul Thomas
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