a very useful book for those people who want to understand SQL in greater depth and to appreciate what it can do.
For a large number of developers working with databases is a bread and butter activity. SQL is the language for querying databases and if you want to advance beyond "select 'item' from table where x=y" then this is a potential candidate.
Using primarily the ANSI SQL-92 standard, the author covers the topics you would expect - database design, normalisation, datatypes and null, expressions (
select, join, group by...) and aggregate functions (count, sum...) and also advanced topics such as arrays, sets, subsets, graphs and optimisation. The text is well laid out with clear case examples, explanations and SQL. However, beginners with databases/SQL will want to start with a different book for more introductory level material.
For those who have a reasonable working knowledge of SQL there will be plenty of material to get your teeth into and plenty of example SQL to experiment with on those complex problems that you have probably dealt with by using simple SQL followed by programmatic manipulation. For instance the section on trees provides SQL to find leaf nodes, or perform subtree insertion or deletion.
One point that came out a number of times is that the various vendors have not fully implemented SQL-92. It would have been useful to have a topic header with a level of vendor compliance. However that is a very minor quibble on what is a very useful book for those people who want to understand SQL in greater depth and to appreciate what it can do.