that is a very poor database design. you need three tables
1) a user table with an id for the user and other info about the user
2) an object table with an id for the object being voted on and other info about the object
3) a voting table with three fields userid, objectid, vote
you would add a new row in the third table every single time an object is voted on. Video "A" gets 100 votes, then it has 100 rows in that table.
Do not store comma separated values in a database, there are too many problems inherent in getting your data tabulated and you are violating 1st normal form of database normalization.