This tag is for all questions related to the teaching of SQL (Structured Query Language) which is a more or less standardized language for obtaining information stored in Relational Databases.
SQL (Structured Query Language) is a largely standardized language for obtaining information from (querying) Relational Databases. It is sometimes used as a synonym for the databases themselves.
Use this tag for all questions related to the teaching of SQL, and, perhaps, many questions related to Relational Databases.
Note that in spite of its name, SQL also has instructions for populating such databases, not just retrieving information from them.