Select Distinct C.Code, AT.Code
FROM dbo.astComponents C
JOIN dbo.astAssetTypes AT ON AT.Id = C.AssetTypeId

WHERE (C.Code= '0738.D100' AND AT.Code = '0738.M00_03.03') Or (C.Code= '0738.D101' AND AT.Code = '0738.L00_04.04')

Except Select C.Code, AT.Code From astComponents C Join astAssetTypes AT ON AT.Id = C.AssetTypeId