fix for when default is zero
fix for when default is zero

robin900/sqlalchemy,halfcrazy/sqlalchemy,alex/sqlalchemy,Cito/sqlalchemy,276361270/sqlalchemy,pdufour/sqlalchemy,Akrog/sqlalchemy,sqlalchemy/sqlalchemy,inspirehep/sqlalchemy,robin900/sqlalchemy,276361270/sqlalchemy,WinterNis/sqlalchemy,monetate/sqlalchemy,zzzeek/sqlalchemy,wfxiang08/sqlalchemy,WinterNis/sqlalchemy,EvaSDK/sqlalchemy,Cito/sqlalchemy,dstufft/sqlalchemy,pdufour/sqlalchemy,halfcrazy/sqlalchemy,olemis/sqlalchemy,davidjb/sqlalchemy,dstufft/sqlalchemy,j5int/sqlalchemy,davidjb/sqlalchemy,davidfraser/sqlalchemy,bootandy/sqlalchemy,hsum/sqlalchemy,bdupharm/sqlalchemy,ThiefMaster/sqlalchemy,monetate/sqlalchemy,bootandy/sqlalchemy,brianv0/sqlalchemy,ThiefMaster/sqlalchemy,hsum/sqlalchemy,elelianghh/sqlalchemy,bdupharm/sqlalchemy,itkovian/sqlalchemy,elelianghh/sqlalchemy,wujuguang/sqlalchemy,sandan/sqlalchemy,EvaSDK/sqlalchemy,alex/sqlalchemy,alex/sqlalchemy,inspirehep/sqlalchemy,j5int/sqlalchemy,epa/sqlalchemy,olemis/sqlalchemy,brianv0/sqlalchemy,itkovian/sqlalchemy,epa/sqlalchemy,sandan/sqlalchemy,wujuguang/sqlalchemy,davidfraser/sqlalchemy,Cito/sqlalchemy,graingert/sqlalchemy,graingert/sqlalchemy,wfxiang08/sqlalchemy,Akrog/sqlalchemy