File with an .SQL extension contains Structured Query Language code in form of text. In such files, commands utilised by a program supporting relational SQL database can be stored (For instance: Microsoft Access, MySQL or FileMaker in form of script for purpose of modifying and downloading a given database).

Instructions that an SQL file may contain are utilised to operate and modify a database. It may include commands creating charts, inserting data blocks, updating them or deleting. Storing and editing files can be achieved via regular text editor, however, usually it is performer in a software environment operating on a given database, with an adequate interface.