Re: bytea question

Well, I don't think you're going to be able to without resorting to
something other than straight sql (a c function would probably work).

You can get the value of a particular byte using get_byte(bytea,int)
but I can't think of a good way outside of some sort of function to
turn that into a split.

Also, get_byte elogs if the int is outside the range of octets on
the bytea.  I would have expected it to work closer to substr on
text.

Stephan Szabo
sszabo@bigpanda.com

On Tue, 15 Aug 2000, mikeo wrote:

> thanks anyway but that doesn't work.  i should've mentioned that i'd
> already tried that in SQL.  my apologies.
>
>
> tig4=# \d x
>           Table "x"
>  Attribute | Type  | Modifier
> -----------+-------+----------
>  tgargs    | bytea |
>
> tig4=# select substr(tgargs,1,5) from x;
> ERROR:  Function 'substr(bytea, int4, int4)' does not exist
>  Unable to identify a function that satisfies the given argument types
>  You may need to add explicit typecasts
>
> tig4=# select substr(tgargs::text,1,5) from x;
> ERROR:  Cannot cast type 'bytea' to 'text'
>
> and other things like varchar, etc.
>
> tig4=# select * from x;
>                                     tgargs
> ------------------------------------------------------------------------------
>  fk_uste_wu_id\000us_states\000web_users\000UNSPECIFIED\000wu_id\000wu_id\000
>  fk_uste_wu_id\000us_states\000web_users\000UNSPECIFIED\000wu_id\000wu_id\000
>  fk_uste_wu_id\000us_states\000web_users\000UNSPECIFIED\000wu_id\000wu_id\000
>
> what i'm looking to do here is to get the table names and column names out
> using sql.  i can do it in perl with a split command on '\' but was curious
> as to how to "SQL" split up a BYTEA type field.
>
> mikeo
>
>
> At 04:38 PM 8/15/00 -0400, mjp@ornl.gov wrote:
> >Try
> >
> >substr(text,int4) or
> >substr(text, int4, int4)
> >
> >For example,
> >
> >
> >% select substr('hi there',4,3);
> > substr
> >--------
> > the
> >(1 row)
> >
> >Morey Parang
> >ORNL
>