SharePoint : How to check for null with a CAML Query?

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Solution

CAML has the IsNull operator,so the query would be:

query.Query = @"<Where><IsNull><FieldRef Name='MessageID' /></IsNull></Where>"

Problem

I have this CAML: ``` query.Query = @"<Where><Eq><FieldRef Name='MessageID' /><Value Type='Text'></Value></Eq></Where>"; ``` This checks if the value of MessageID = string.empty() What I would like to check for is null.... not empty string... Is this possible with CAML?

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