MySQL Using Group By, Need to add fields where answer is reliant on another fields data
Your question is not clear enough, but the following query would provide you with the results you specify as "AFTER :)"

SELECT  inventory.`CODE` AS `Item No.`,
        inventory.INV_DESCRIPTION AS Description,
        SUM(CASE WHEN inventory.WHSE = '00' THEN inventory.ONHAND ELSE 0 END) AS `On Hand (LA)`,
        SUM(CASE WHEN inventory.WHSE = '10' THEN inventory.ONHAND ELSE 0 END) AS `On Hand (SF)`,
        SUM(CASE WHEN inventory.WHSE = '20' THEN inventory.ONHAND ELSE 0 END) AS `On Hand (HP)`,
        SUM(CASE WHEN inventory.WHSE = '50' THEN inventory.ONHAND ELSE 0 END) AS `On Hand (CHINA)`,
        SUM(CASE WHEN inventory.WHSE = '70' THEN inventory.ONHAND ELSE 0 END) AS `On Hand (INDO)`
FROM inventory
WHERE inventory.WHSE IN ('00', '10', '20', '50', '70') AND 
      inventory.PROD IN ('A', 'A-70', 'B', 'C', 'S', 'KIT', 'SET')
GROUP BY inventory.`CODE`, inventory.INV_DESCRIPTION
ORDER BY 1