First, if you want to extract and compare two columns, your query needs to select two columns. Your query is only extracting column 1.

It's worse than this. You define 2 SQL operations, an insert and a select. You are doing the fetchrow on the insert, which is unlikely to do much of anything.

Sure sounds like homework to me. If you want help:

1. use mysql cli to display the table you want to parse, and cut/paste that to your post
2. supply code that actually runs (but may not be doing what you want), instead of a snippet that references undefines (ie, @word), and clearly does nothing.
3. There are many, many ways to accomplish the comparison/sorting you want. If you don't even know how to go about figuring out common elements in 2 arrays, then your issue is foundational.