I have three lists like List1, List2, List3. I need to retrieve an item based on conditions, Is this possible to query the items from multiple lists using Caml query builder tool U2U. I am not sure about SiteData Query, So Please Suggest me an idea to achieve this.
you can use SpsiteDataQuery. Also you can try to use OOTB content query web part. From Link above
query.Lists = "<Lists><List ID='7A9FDBE6-0841-430a-8D9A-53355801B5D5' /><List ID='3D18F506-FCA1-451e-B645-2D720DC84FD8' /></Lists>";
It is not possible using Caml query builder tool U2U.
you have to build your CAML Query as per below link : Using CAML Query to Retreive from Multiple Lists