If I try it without the single quotes within the func declaration, I get a strict subs error

Now how to get DBI::Shell to interact with the user so they have access to this function?

#!/usr/bin/perl -w
# create a SQLite test database
use strict;
use DBI;

my $db = shift || 'no_name.splite';
my $dbh = DBI->connect("dbi:SQLite:$db", "","",
        {RaiseError => 1, 
         sqlite_see_if_its_a_number => 1, 
          PrintError=>0})
   or die "can't connect\n";

$dbh->func('sqrt_s_s', -1, 'sqrt_sum_of_sqrs', 'create_function'); #ne
+ed length function
sub sqrt_sum_of_sqrs {
    my $sum_sqrs = 0.0;
    map {$sum_sqrs += $_**2} @_;
    return sqrt($sum_sqrs);
}

my $sth;

my @rowa = $dbh->selectrow_array("select 3 as A,4 as B, sqrt_s_s(3,4) 
+as C");
print join ("\t",@rowa) ;
[download]

If I try it without the single quotes within the func declaration, I get a strict subs error

Something like this?

#!/bin/env perl
# create a SQLite test database
use strict;
use warnings;
use DBI;

my $db = shift @ARGV || 'no_name.splite';

my $dbh = DBI->connect(
    "dbi:SQLite:$db", "", "",
    {
        RaiseError => 1,
        sqlite_see_if_its_a_number => 1,
        PrintError => 0
    }
);

$dbh->func('sqrt_s_s', -1, \&sqrt_sum_of_sqrs, 'create_function'); # n
+eed length function

my @rowa = $dbh->selectrow_array( "select 3 as A, 4 as B, sqrt_s_s( 3,
+ 4 ) as C" );

print join( "\t", @rowa ), "\n";

sub sqrt_sum_of_sqrs {
    my $sum_sqrs = 0.0;
    map { $sum_sqrs += $_ ** 2 } @_;
    return sqrt( $sum_sqrs );
}
[download]

Update: So now you need to research three things.

1. How would you prompt a user for input?
2. How to get the user input?
3. How do you pass the user input into your function?

My past research peaked my interest in the command line tool dbish. So my answers are as follows.

>Update: So now you need to research three things.

>How would you prompt a user for input?

via dbish (or DBI::Shell interface)

>How to get the user input?

via dbish (or DBI::Shell interface)

>How do you pass the user input into your function?

I'm thinking that there should already be code that has performed the ->func method.

I'm hoping to be able to type into the dbish interface something like this:

select 3 as oposite, 4 as adjacent, sqrt(3,4) as hyp

and get

3 4 5

as a result.