I am doing a select into a list of variables, but I don't know how to
tell if the select returns no rows, in which case I don't want to
proceed. Is there a success value or other technique?

Thanks!
Tony

On Thu, 18 Oct 2007 08:18:51 -0700, Tony wrote:
> I am doing a select into a list of variables, but I don't know how to
> tell if the select returns no rows, in which case I don't want to
> proceed. Is there a success value or other technique?

Some language libraries have a function for determining how many rows
are returned in a data set. Others may leave you to do something like

result_set = execute_mysql_query(my_query)
WHILE (my_row = get_mysql_row(result_set) IS SUCCESSFUL)
DO stuff in a loop
DONE

--
50. My main computers will have their own special operating system that will
be completely incompatible with standard IBM and Macintosh powerbooks.
--Peter Anspach's list of things to do as an Evil Overlord

On Oct 18, 11:42 am, "Peter H. Coffin" <hell...@ninehells.com> wrote:
> On Thu, 18 Oct 2007 08:18:51 -0700, Tony wrote:
> > I am doing a select into a list of variables, but I don't know how to
> > tell if the select returns no rows, in which case I don't want to
> > proceed. Is there a success value or other technique?
>
> Some language libraries have a function for determining how many rows
> are returned in a data set. Others may leave you to do something like
>
> result_set = execute_mysql_query(my_query)
> WHILE (my_row = get_mysql_row(result_set) IS SUCCESSFUL)
> DO stuff in a loop
> DONE
>
> --
> 50. My main computers will have their own special operating system that will
> be completely incompatible with standard IBM and Macintosh powerbooks.
> --Peter Anspach's list of things to do as an Evil Overlord

I am in a stored procedure, so no PHP or other functions are
available. Just native MySQL operations. Thanks, Tony

== Quote from Tony (google@sendto.org)'s article
> On Oct 18, 11:42 am, "Peter H. Coffin" <hell...@ninehells.com> wrote:
> > On Thu, 18 Oct 2007 08:18:51 -0700, Tony wrote:
> > > I am doing a select into a list of variables, but I don't know how to
> > > tell if the select returns no rows, in which case I don't want to
> > > proceed. Is there a success value or other technique?
> >
> > Some language libraries have a function for determining how many rows
> > are returned in a data set. Others may leave you to do something like
> >
> > result_set = execute_mysql_query(my_query)
> > WHILE (my_row = get_mysql_row(result_set) IS SUCCESSFUL)
> > DO stuff in a loop
> > DONE
> >
> > --
> > 50. My main computers will have their own special operating system that will
> > be completely incompatible with standard IBM and Macintosh powerbooks.
> > --Peter Anspach's list of things to do as an Evil Overlord
> I am in a stored procedure, so no PHP or other functions are
> available. Just native MySQL operations. Thanks, Tony

what you need is a condition and a handler. the following will set a phoney
sqlstate (there is one for no record found). if mysql hits that sqlstate it'll set
the exit_loop to 1, you'd check that in your logic and exit accordingly and move
on to the next record.

DECLARE CONTINUE HANDLER FOR SQLSTATE '999999' SET exit_loop = 1; DECLARE CONTINUE
HANDLER FOR SQLSTATE '939999'
BEGIN
statement_list
END;



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