Re[2]: lower() for varchar data by creating an index

OK, but how can I delete this function? By attempting to remove it I've got an error:

my-db=> DROP FUNCTION lower(varchar);
ERROR: RemoveFunction: function "lower" is built-in

I want to delete it because I receive strange sorting results (you can read about them in my mail with
subj "strange ORDER BY implementation").

Alex

Wednesday, May 17, 2000, 6:31:50 PM Mitch wrote:

MV> CREATE function lower(varchar) returns text as 'lower' language 'internal'
MV> with (iscachable);

MV> It's a bit slower than if it was actually in the backend but it's a very
MV> tiny difference. I spoke to Tom Lane about this, it's on the TODO list I
MV> believe for 7.1. In the meantime the above will work great..

MV> - Mitch

MV> "The only real failure is quitting."

MV> ----- Original Message -----
MV> From: Alex Guryanow <gav(at)nlr(dot)ru>
MV> To: <pgsql-sql(at)postgresql(dot)org>
MV> Sent: Wednesday, May 17, 2000 3:51 AM
MV> Subject: [SQL] lower() for varchar data by creating an index

>> Hi,
>>
>> I have a table called t1 with field f1 of type varchar(40):
>>
>> CREATE TABLE t1 (f1 varchar(40));
>>
>> To make a case insensitive search I build the query like
>>
>> SELECT f1 FROM t1 WHERE lower( f1 ) LIKE 'alex%';
>>
>> This works fine. But when I try to make an index to speed up the query
MV> using the command
>>
>> CREATE INDEX t1_f1_idx ON t1 (lower(f1));
>>
>> I receive the following error:
>>
>> ERROR: DefineIndex: function 'lower(varchar)' does not exist
>>
>> Why by executing the query the function 'lower(varchar)' exists and by
MV> creating the index don't?
>>
>> I use Postgres 7.0.
>>
>> Best regards,
>> Alex
>>
>>
>>