Virtually every company that operates online uses some kind of database to store information. SQL servers are one of the most commonly used tools to deploy and maintain such databases.

SQL servers are synonymous with the concept of relational databases. Relational database software makes up 7 of the 10 most commonly used database management (DBMS) systems, according to DB-Engines.

People do not always think of, or want, a literal, physical server when they say "SQL server." Often, professionals use the term to refer to the database itself, rather than the computing server that delivers it.