In this blog we will learn How to pass null and not null operator in FetchXML?

First learn about What is a NULL Value?

A field with a NULL value is a field with no value.
If a field in a table is optional, it is possible to insert a new record or update a record without adding a value to this field. Then, the field will be saved with a NULL value.

Note: Always remember this point, A NULL value is different from a zero value or a field that contains spaces.

How to use null operator in FetchXML ?
The following FetchXML lists all customers with a NULL value in the “Address” field:

<fetch mapping="logical" version="1.0">
  <entity name="customers">
    <attribute name="customername" />
    <attribute name="contactname" />
    <attribute name="address" />
    <filter>
      <condition attribute="address" operator="null" />
    </filter>
  </entity>
</fetch>

Pass not-null operator in FetchXML

The NOT-NULL operator is used to test for non-empty values (NOT NULL values).

The following FetchXML lists all customers with a value in the “Address” field:

<fetch mapping="logical" version="1.0">
  <entity name="customers">
    <attribute name="customername" />
    <attribute name="contactname" />
    <attribute name="address" />
    <filter>
      <condition attribute="address" operator="not-null" />
    </filter>
  </entity>
</fetch>