Item Unit of Measure Conversion Integrity SQL Query Generator

SELECT i.item_no, i.purch_uom, i.stock_uom
FROM item_master i
WHERE i.purch_uom <> i.stock_uom
  AND NOT EXISTS (
    SELECT 1 FROM item_uom_conversion c
    WHERE c.item_no = i.item_no
      AND c.from_uom = i.purch_uom
      AND c.to_uom = i.stock_uom
  )
ORDER BY i.item_no;

SELECT c.item_no, c.from_uom, c.to_uom, c.factor
FROM item_uom_conversion c
WHERE c.factor IS NULL
   OR c.factor <= 0
ORDER BY c.item_no, c.from_uom;

SELECT a.item_no, a.from_uom AS uom_a, a.to_uom AS uom_b,
       a.factor AS factor_ab, b.factor AS factor_ba,
       a.factor * b.factor AS product
FROM item_uom_conversion a
JOIN item_uom_conversion b
  ON b.item_no = a.item_no
 AND b.from_uom = a.to_uom
 AND b.to_uom = a.from_uom
WHERE a.from_uom < a.to_uom
  AND ABS(a.factor * b.factor - 1) > 0.0001
ORDER BY a.item_no;