A search operator - sometimes referred to as a search parameter - is a character or string of characters used in a search engine query to narrow the focus of the search. In Explorer, operators represent a filtering action to be performed. Below is a list with definitions of the operators found in Explorer.
​

​IS NOT NULL - The IS NOT NULL operator indicates a search within a particular property has a value.
That is, this operator will effectively eliminate null properties from your results

IS NULL - The IS NULL operator indicates a search within a particular property does not have a value.
That is, this operator will effectively identify null properties in your results

INCLUDES - The INCLUDES operator indicates a search for any of the specified words or phrases within a particular property

DOES NOT INCLUDE - The DOES NOT INCLUDE operator indicates a search that does not contain any of the specified words or phrases within a particular property

IS EQUAL TO - The IS EQUAL TO operator is true if the item(s) specified has an exact match with the within a particular property

IS NOT EQUAL TO - The IS NOT EQUAL TO operator is true if the item(s) specified is not equal to an exact match within a particular property

IS GREATER THAN - The IS GREATER THAN operator is true if the item(s) specified has a greater value than a particular property

​IS LESS THAN - The IS LESS THAN operator is true if the item(s) specified has a lesser value than a particular property

IN THE LAST - The IN THE LAST operator selects values over the last years, quarters, months, weeks, days, etc.

​IS AFTER - This operator selects values that fall after a given date

IS BEFORE - This operator selects values that fall before a given date

IS ON OR AFTER - This operator selects values that fall on and/or after a given date

IS ON OF BEFORE - This operator selects values that fall on and/or before a given date