TSQL and PLSQL

TSQL is Transact SQL (Structured Query Language)

Basically, TSQL is Microsofts (and Sybases?) variant of the SQL language and PLSQL is Oracles variant. Both have taken the SQL ANSI standard and extended to work with their database implementations. I've never worked with PLSQL, but know that if you use any of the extensions to TSQL or PLSQL, it will not port easily to the others database very easily. SQL purists and vendors that want to be able to sell their software to run on either databasesay that you should try to stick to the SQL ANSI standard to make it more portable.

Hope this helped!