There does not seem to be anything about that covers exactly what I want to do, so here goes:

The scenario is this: I have several stored procedures which take little input and give little output. Typically they take a parameter as either a number or string, and expect either a number or string back. 

my $var_with_chars = "a string";
my @result = [];
        $sql = 'call register_hit("'.$var_with_chars.'",@hit_count)'; 
+#watch out for the "@"!
        my $sth = $db_handle->prepare($sql);
        $sth->execute() || die $DBI::errstr;
        $sth->finish;

        # Now get the output variable

        @result = $db_handle->selectrow_array('SELECT @hit_count');# |
+| die $DBI::errstr;
        print "result=", $result[0], "\n";

[download]

The above code assumes that you are using Perl DBI and DBD::Mysql and have created a valid database handle, $db_handle.

You will note the @hit_count is a made up variable, only used with the database connection and does not need to be declared locally. All other variables are local. You will also note the way I have had to construct the $sql statement. This is so that when passed to DBD::Mysql the contents of the variable are passed not the variable name. If you try to reverse the style of the quotes then perl tries to pass something for @hit_counter, if it is not defined you will get an error saying so, and if it is it will be evaluated as an array reference causing DBD::Mysql to crash.

I hope that helps.

In reply to Calling MySQL stored procedures with in and out parameters by Benedict White

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