Additional Resources

Oracle Documentation

Sample Schemas

CASE Expressions

Related Articles

Sample Schemas article on OTN

Original DECODE paper

Daniel Morgan's DECODE and CASE reference

AskTom thread on deciphering execution plans,F4950_P8_CRITERIA:231814117467,


I'd like to thank the following people for sparing some of their time to read through the paper, checking it for accuracy and making some very useful suggestions for improvement. As usual, the final decisions and all of the mistakes are mine and there would have been more without their assistance.

Andrew Campbell, Sun Microsystems

Colin Garside, BUPA

John Gilroy, Ask Jeeves

Jeffrey Kemp

Jari Kuhanen, Sun Microsystems

If you spot any errors or can suggest improvements, please feel free to drop me an email at

Improving SQL efficiency using CASE