SQLPL stands for Structured Query Language Procedural. It was developed by IBM just as a set of command to extend the use of SQL in the database system. SQ LP provides procedural programmability which boos the querying commands of the SQL.
SQL PL has a set of set of stored procedures which can run inside both DB2 and DB1. It provides statements for declaring variables and condition handlers which are used to implement procedural logic. The language can also be used to implement procedural logic in SQL procedures.