implement data api level sub-join function
implement data api level sub-join function

PATRIC3/p3_api,aswarren/p3_api,maovt/p3_api,maovt/p3_api,maovt/p3_api,maovt/p3_api,maovt/p3_api,aswarren/p3_api,maovt/p3_api,PATRIC3/p3_api