[<index>/] [!] [<operator>] [$] <param> = <value>
Default combinatorial function AND prefixing with ! switches to OR
index - sets the order in the expression
operator is the expression operator (default is eq). Can be one of eq, lt, gt, le, ge, like, null, isnotnull
$ indicates that the parameter is a variable (e.g. $currentDate, $currentUser, $currentYear etc)
Sorting can be added by:
sort(attr1, attr2+)
Default direction is descending, adding the suffix + will make it ascending