Conditions that define query criteria can concern the values of object characteristics or links, or the existence or non-existence of a link. Note that conditions can be grouped.

A condition indicates the query criterion or criteria. A condition is optional: if there is no condition, the result is the set or the combination of sets indicated after the From operator. If no set was specified, the result contains all objects of the type indicated.

A condition can consist of basic conditions connected by the or, and, and not operators. You can use brackets according to the rules indicated for combining sets.

A condition usually consists of:

This restricts the query to target objects fulfilling query conditions.