I believe, there is also nothing wrong in query you built. Why is it not working?

SELECT

OYHSSQ,

OYNMTP,

OYNAME,

OYADD1,

OYADD2,

OYCITY,

OYSTAT,

OYZIP4,

OYCNTC,

OYPHAR,

OYPHXX,

OYPH04,

OYPHEX,

OYFL18,

OYADD3,

OYCTID,

OYCTCD,

OYADD4,

OYPHNA

FROM TABLE_B

WHERE NOT EXISTS (

SELECT

OYHSSQ, OYNMTP, OYNAME, OYADD1, OYADD2,

OYCITY, OYSTAT, OYZIP4, OYCNTC, OYPHAR,

OYPHXX, OYPH04, OYPHEX, OYFL18, OYADD3,

OYCTID, OYCTCD, OYADD4, OYPHNA

FROM Table_A

WHERE TABLE_B .OYHSSQ = Table_A.OYHSSQ AND TABLE_B .OYNMTP = Table_A.OYNMTP

)