SELECT
B.BOMREC_CODE AS PRODUCT_CODE,
S.NAME AS PRODUCT_NAME,
B.BOMREC_MATERIALCODE AS SUB_MATERIAL,
S1.NAME AS SUB_MATERIAL_NAME,
B.BOMREC_ALTCODE AS ALTERNATIVE,
(SIP.SF_QUANTITY - SIP.SF_NEWSHIPPED) AS OPEN_ORDERQT
SIP.DLVDATE AS DELIERY_DATE
FROM BOMU01T B
LEFT JOIN STOCK00 S ON TRIM(S.CODE)=TRIM(B.BOMREC_CODE)
LEFT JOIN STOCK00 S1 ON TRIM(S1.CODE)=TRIM(B.BOMREC_MATERIALCODE)
LEFT JOIN STOCK40T SIP ON TRIM(SIP.CODE)=TRIM(B.BOMREC_CODE)
WHERE B.BOMREC_CODE='2496802300'
ORDER BY 1 DESC
Looks like your missing a Group by clause
Try This:
SELECT
B.BOMREC_CODE AS PRODUCT_CODE,
S.NAME AS PRODUCT_NAME,
B.BOMREC_MATERIALCODE AS SUB_MATERIAL,
S.NAME AS SUB_MATERIAL_NAME,
B.BOMREC_ALTCODE AS ALTERNATIVE,
(SIP.SF_QUANTITY - SIP.SF_NEWSHIPPED) AS OPEN_ORDERQT
SIP.DLVDATE AS DELIERY_DATE
FROM BOMU01T B
LEFT JOIN STOCK00 S ON TRIM(B.BOMREC_CODE)= TRIM(S.CODE)
AND TRIM(B.BOMREC_MATERIALCODE)=TRIM(S.CODE)
LEFT JOIN STOCK40T SIP ON TRIM(B.BOMREC_CODE)=TRIM(SIP.CODE)
WHERE B.BOMREC_CODE='2496802300'
ORDER BY 7 DESC;