A question asked about data contained in two or more tables in a relational database. The relational query must specify the tables required and what the condition is that links them; for example ...

Tables within a database management system (DBMS) need primary keys and defined indexes in order for the DBMS to have the opportunity to provide good query performance. Without indexing, the worst ...

Optimizing the performance of operational databases and the applications that access them is a constant battle for DBAs. Of course, writing efficient SQL is the most important aspect of ensuring ...