Don't insert plain text into a SQL statement!!! Escape properly or use placeholders.

my $sql = "SELECT script FROM scripts where name=?";
my $sth = $dbh->prepare($sql);
$sth->execute($ref->{name});
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What's with putting everything in quotes?

"$sql"                 ->  $sql
"$row_hash->{script}"  ->  $row_hash->{script}
"$script"              ->  $script
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Or a here-doc?

$r->puts(<<"END");     \
$post                   >  $->puts($post)
END                    /
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Why loop when you only want one variable?

my $row_hash = $sth->fetchrow_hashref()
   or die(...);

$script = $row_hash->{script};
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Finally, "doesn't work" is a very useless problem description. Please provide more details.

...although returning one probably won't help if you use it that way.

my $result = eval $script;
defined($result)
   or die(...);

$post .= $result;
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