SQL or Structured Query Language is a language which is used to communicate with a relational database. It provides a way to manipulate and create databases. On the other hand, PL/SQL is a dialect of SQL which is used to enhance the capabilities of SQL. It was developed by Oracle Corporation in the early 90’s. It adds procedural features of programming languages in SQL.
In SQL single query is being executed at once whereas in PL/SQL a whole block of code is executed at once.
SQL is like the source of data that we need to display on the other hand PL/SQL provides a platform where the SQL the SQL data will be shown.
SQL statement can be embedded in PL/SQL, but PL/SQL statement cannot be embedded in SQL as SQL do not support any programming language and keywords.