fixes for PG, Mysql
fixes for PG, Mysql

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