Practical SQL Handbook, The: Using SQL Variants, Fourth Edition

Summary

This chapter has introduced some real-world SQL as well as cautions on common mistakes. The first section includes the following:

• Thinking conditionally— using CASE, COALESCE, and variants of these two keywords to make IF-like choices

• Formatting and displaying data— learning how to split columns, how to join columns, and how to convert columns from one datatype to another

• Playing with patterns— handling uppercase/lowercase issues, using complex expressions in predicates, and working with date data

The second section gives examples of common mistakes:

• Mixing up DISTINCTs

• Creating report-style displays

• Finding the “first” row

For more information on these topics, see Appendix E, Resources.