How to use User Name, User Id , Logged in User Id in SharePoint CAML Query

CAML query is used to retrieve data from SharePoint lists. To perform a filter based on Person or User Group or a specific user id follow any of the below approach

All the below queries are based on a SharePoint List Column named as “User ID” of type Person or Group

Option 1 –  If you know the display name of the user

 <Where>
   <Eq>
      <FieldRef Name='User_x0020_ID' />
      <Value Type='User'>System Account</Value>
   </Eq>
 </Where>

Option 2 – If you know the User Id ( not the login id)

 <Where>
    <Eq>
       <FieldRef Name='User_x0020_ID' LookupId='True'  />
       <Value Type='User'>1073741823</Value>
    </Eq>
 </Where>

Option 3 – If you would like to filter based on current user (logged in User )

 <Where>
    <Eq>
       <FieldRef Name='User_x0020_ID'/>
       <Value Type='User'><UserID/></Value>
    </Eq>
 </Where>