Question

SELECT 
    ITM, OPB, INB, 
    (SELECT CODE FROM CodeandDescription WHERE ITM = RM_S4G100_KYBIN.ITM) As CODE, 
    (SELECT ITMD FROM CodeandDescription WHERE ITM = RM_S4G100_KYBIN.ITM) As ITMD, 
    CLB, DTE 
FROM 
    RM_S4G100_KYBIN 
WHERE 
    (DTE >= '01 Oct 2011') and (DTE <= '31 Oct 2011') 
    AND
    (SELECT ITMD 
     FROM CodeandDescription 
     WHERE ITM = RM_S4G100_KYBIN.ITM) IS NOT NULL
    AND
    (OPB <> '0.00000' OR INB <> '0.00000' OR CLB <> '0.00000') 
ORDER BY 
    ITMD, DTE

Answer 1

If you perform INNER JOIN instead of additional SELECT for CODE and ITMD, that should speed up the query.

SELECT ITM, OPB, INB, CodeandDescription.CODE As CODE, CodeandDescription.ITMD As ITMD,
CLB, DTE FROM RM_S4G100_KYBIN INNER JOIN CodeandDescription ON CodeandDescription.ITM = RM_S4G100_KYBIN.ITM
WHERE (DTE >= '01 Oct 2011') and (DTE <= '31 Oct 2011') and
CodeandDescription.ITMD is not NULL  and 
(OPB <> '0.00000' or INB <> '0.00000' or CLB <> '0.00000')
ORDER BY ITMD, DTE