
Teach Yourself SQL in 21 Days, Second Edition


Week 3 In Review
This week should have been very productive. Week 3 shows you the flexibility
of SQL, explains how you can apply these features to real-world problems,
and introduces some popular extensions to SQL. You should know how to use
the tools that are available with your implementation of SQL to make your
code more readable. By now you realize that all implementations of SQL
share the same general concepts, although the syntax may differ slightly.
You should have a clear understanding of the data dictionary, what data
it contains, and how to retrieve useful information from it. If you understand
how to generate SQL from another SQL statement, you should be ready to
fly to unlimited heights.
What about errors? You will never be immune from syntax errors or logical
mistakes, but as you gain experience with SQL, you will learn how to avoid
many problems. But then again, errors can be excellent learning opportunities.


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