In previous chapters we have looked at some basic data retrieval filtering techniques using comparison operators and wildcards. Whilst this approaches approach to data filtering are is fine for basic searching, more advanced searching quickly becomes cumbersome using these techniques.
In this chapter we will look at yet another filtering and searching technique supported by MySQL called ''regular expressions''.
== What are Regular Expressions? ==
<google>ADSDAQBOX_FLOW</google>
Exception encountered, of type "Error"
[0b15221a] /index.php/Special:MobileDiff/7873 Error from line 434 of /var/www/techotopia/includes/diff/DairikiDiff.php: Call to undefined function each()
Backtrace:
#0 /var/www/techotopia/includes/diff/DairikiDiff.php(544): DiffEngine->diag()
#1 /var/www/techotopia/includes/diff/DairikiDiff.php(344): DiffEngine->compareSeq()
#2 /var/www/techotopia/includes/diff/DairikiDiff.php(227): DiffEngine->diffLocal()
#3 /var/www/techotopia/includes/diff/DairikiDiff.php(721): DiffEngine->diff()
#4 /var/www/techotopia/includes/diff/DairikiDiff.php(859): Diff->__construct()
#5 /var/www/techotopia/includes/diff/DairikiDiff.php(980): MappedDiff->__construct()
#6 /var/www/techotopia/extensions/MobileFrontend/includes/diff/InlineDiffFormatter.php(99): WordLevelDiff->__construct()
#7 /var/www/techotopia/includes/diff/DiffFormatter.php(140): InlineDiffFormatter->changed()
#8 /var/www/techotopia/includes/diff/DiffFormatter.php(82): DiffFormatter->block()
#9 /var/www/techotopia/extensions/MobileFrontend/includes/diff/InlineDifferenceEngine.php(117): DiffFormatter->format()
#10 /var/www/techotopia/includes/diff/DifferenceEngine.php(797): InlineDifferenceEngine->generateTextDiffBody()
#11 /var/www/techotopia/includes/diff/DifferenceEngine.php(728): DifferenceEngine->generateContentDiffBody()
#12 /var/www/techotopia/extensions/MobileFrontend/includes/specials/SpecialMobileDiff.php(241): DifferenceEngine->getDiffBody()
#13 /var/www/techotopia/extensions/MobileFrontend/includes/specials/SpecialMobileDiff.php(135): SpecialMobileDiff->showDiff()
#14 /var/www/techotopia/extensions/MobileFrontend/includes/specials/MobileSpecialPage.php(53): SpecialMobileDiff->executeWhenAvailable()
#15 /var/www/techotopia/includes/specialpage/SpecialPage.php(384): MobileSpecialPage->execute()
#16 /var/www/techotopia/includes/specialpage/SpecialPageFactory.php(553): SpecialPage->run()
#17 /var/www/techotopia/includes/MediaWiki.php(281): SpecialPageFactory::executePath()
#18 /var/www/techotopia/includes/MediaWiki.php(714): MediaWiki->performRequest()
#19 /var/www/techotopia/includes/MediaWiki.php(508): MediaWiki->main()
#20 /var/www/techotopia/index.php(41): MediaWiki->run()
#21 {main}