Chapter 9 Query Language Reference : Operators for Other Expressions

Operators for Other Expressions
Between operator for range expressions. Range is inclusive.
x and y must all be number types, or all be Datetime types.
Inclusion operator. Checks if an expression is in a group of items.
$name
name has no type. It is just a label.
The type of $name is determined by its surrounding expression. For example, in the expression:
$minimum is a bind variable of type double.