extract-data

use feature qw(say);
use strict;
use warnings;

{
    my @tests = (
        [1, 'Empty table error - data load failed.'],

        [1, {'message' => 'Prepare failed: [Teradata][ODBC Teradata Driver][Teradata Database](-5628)Column DWH_TENANT_ID not found in Q. (SQL-HY000) '}],

        [1, {'message' =>
           {'message' => 'Prepare failed: [Teradata][ODBC Teradata Driver][Teradata Database](-5628)Column not found . (SQL-HY000) '}}],

        [1, {'message' =>
          {'message' =>
           {'message' => 'Prepare failed: [Teradata][ODBC Teradata Driver][Teradata Database](-5628)Column not found . (SQL-HY000) ' }}}],
        [2, {'message' =>
          {'message' =>
           {'sql_stmt' => ' select * from db.table',
            'message' => 'Execute failed: [Teradata][ODBC Teradata Driver][Teradata Database](-2631)Transaction ABORTed due to Deadlock. (SQL-40001)' }}}],
    );

    for my $i (0..$#tests) {
        my $test = $tests[$i];
        my $type = $test->[0];
        my $hash = { "_errlist_" => [$test->[1]] };
        if ( $type == 1 ) {
            my $errmsg = extract_err( $hash->{_errlist_}[0], $type );
            say "Test #$i: $errmsg";
        }
        elsif ( $type == 2 ) {
            my $sql_statement = $hash->{_errlist_}[0]{message}{message}{sql_stmt};
            say "Test #$i: (sql) : $sql_statement";
        }
    }
}

sub extract_err {
    my ( $hash ) = @_;

    if (ref $hash eq "HASH") {
        return extract_err( $hash->{message} );
    }
    elsif (!(ref $hash)) {
        return $hash;
    }
    else {
        die "Unexpected reference type: ", ref $hash, "\n";
    }
}