Structured Query Language is mainly designed for managing data stored in relational database management system (RDBMS). SQL can be used to perform task like retrieving data or updating data in a database. There are n-number of relational database management system available in market that use SQL which includes Oracle, Sybase, Access, Microsoft SQL Server etc., and SQL is considered as the standard language for interacting with any RDBMS.
PL/SQL is extension of SQL along with the procedural features of programming language. It supports conditional looping, variables and exceptions. It was introduced by Oracle Corporation in early 1990’s to enhance the features of SQL.