Also known as T-SQL, Transact-SQL is an extension of SQL developed by Microsoft and Sybase which is used to interact with relational databases. As such, T-SQL is key for developers using Microsoft SQL Server, the database management system created by the Redmond giant. All of the communications with this system are carried out through T-SQL statements, which explains why this language is popular among certain users – it’s practically mandatory! 

SQL ( (listen) S-Q-L, "sequel"; Structured Query Language) is a domain-specific language used in programming and designed for managing data held in a relational database management system (RDBMS), or for stream processing in a relational data stream management system (RDSMS). It is particularly useful in handling structured data, i.e.