Скачать или смотреть SQL Tutorial - Case Distinctions with UNION, CASE, COALESCE | Database Tutorial 5r

In this lecture of the databases course we learn how to perform case distinctions in SQL using UNION, CASE and COALESCE. The most portable way to do case distinctions in SQL is the UNION operation. However, many system support the more succinct CASE operation. COALESCE allows to replace null values by a default value.

This is the databases online course given at the Vrije Universiteit Amsterdam by Jörg Endrullis. The course objective is to obtain a good understanding of relational database systems from the user perspective. This includes the ability to develop conceptual database models, as well as key concepts and skills in relational database theory and practice.

Among others, we treat in this course the following subjects:
(a) entity–relationship diagrams for the design of database schemata,
(b) the relational database model and integrity constraints,
(c) SQL (structured query language) for retrieving information from relational databases,
(d) database normalisation and functiona dependencies (reasoning about good database design),
(e) transactions and concurrency control.

The slides are based on work by Peter Boncz and Torsten Grust.