change $sth->execute(1, 10); to $sth->execute();
Please don't. Placeholders prevent SQL injections and allow caching of prepared statements, so:
- Change the value "E" in $sql to a single, unquoted ?
- Change the execute parameters to ("E")
More information: DBI, Bobby Tables, Re: Counting rows Sqlite, Re^2: Massive Memory Leak, Re^5: Variable interpolation in a file to be read in.
Today I will gladly share my knowledge and experience, for there are no sweeter words than "I told you so". ;-)