[mysql] refactoring for better readability.
[mysql] refactoring for better readability.

manolama/dd-agent,takus/dd-agent,takus/dd-agent,jyogi/purvar-agent,indeedops/dd-agent,cberry777/dd-agent,manolama/dd-agent,jyogi/purvar-agent,takus/dd-agent,jyogi/purvar-agent,takus/dd-agent,manolama/dd-agent,Wattpad/dd-agent,indeedops/dd-agent,cberry777/dd-agent,jyogi/purvar-agent,cberry777/dd-agent,takus/dd-agent,jyogi/purvar-agent,indeedops/dd-agent,indeedops/dd-agent,cberry777/dd-agent,Wattpad/dd-agent,cberry777/dd-agent,manolama/dd-agent,manolama/dd-agent,Wattpad/dd-agent,Wattpad/dd-agent,Wattpad/dd-agent,indeedops/dd-agent