When migrating from Voyager to Alma, you may want to do some Call Number cleanup.  That includes identifying MFHD records with null Call Numbers.  Please note that for some MFHDs (such as electronic resources) it is acceptable to have no call number.

This query, which can be run using Voyager Prepackaged Access Reports, finds MFHD records where the call number is null and there are item records attached to the MFHD.

SELECT DISTINCT MFHD_MASTER.MFHD_ID, ITEM.ITEM_ID
FROM ITEM INNER JOIN (MFHD_MASTER
INNER JOIN MFHD_ITEM ON MFHD_MASTER.MFHD_ID = MFHD_ITEM.MFHD_ID)
ON ITEM.ITEM_ID = MFHD_ITEM.ITEM_ID
WHERE (((MFHD_MASTER.DISPLAY_CALL_NO) Is Null));

For other queries that may be useful, see my "Surviving Almanado: tips for a successful pre-implementation" presentation's Accompanying Materials.
 
If you need assistance in running custom SQL queries in Prepackaged Access Reports, consult the Voyager Customer Listserv.