Not sure what version of QRadar you are on, but the best cheat sheet is to use the new Show AQL button in QRadar 7.3.2 versions. This allows you to convert any query to view the AQL being run on the back end and understand how the search is run. You can then add QRadar apps or content packs that have searches and view the associated AQL query.
Here are some links with examples:
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Jonathan Pechta
QRadar Support Content Lead
Support forums: ibm.biz/qradarforums
jonathan.pechta1@ibm.com------------------------------