The History of SQL Standards
1. SQL or Structured Query Language was developed by IBM for their product "System R".
Later ANSI made it as a Standard on which all Query Languages are based upon and have extended this to create their own DataBase Query Language suits. The first standard was SQL-86 and latest being SQL:2016
2. T-SQL or Transact-SQL was developed by Sybase and later co-owned by Microsoft SQL Server.
3. PL/SQL or Procedural Language/SQL was Oracle Database, known as "Relation Software" that time.