replace panic with error, handle missing error case
replace panic with error, handle missing error case

nanata1115/mysql,jockchou/mysql,VividCortex/mysql,zhgo/mysql,Freeaqingme/golang-sql-driver-mysql,helight/helight_code,bookerzzz/mysql,hyperworks/mysql,Vorstack/mysql,rafaeljusto/mysql,wfxiang08/mysql,helight/helight_code,helight/helight_code,helight/helight_code,methane/mysql,henrylee2cn/mysql,helight/helight_code,Frca/mysql,cw2018/mysql,sunjian1/mysql,segmentio/mysql,roth1002/mysql,chinanjjohn2012/mysql,go-sql-driver/mysql,VividCortex/mysql,LightKool/mysql-go,Go-SQL-Driver/MySQL,cxflag203/mysql,yonglehou/mysql,methane/mysql,helight/helight_code,eklitzke/mysql,netroby/mysql,hebihui/mysql,LightKool/mysql-go,tmulchay/mysql,helight/helight_code,muthusubbu459/mysql,siriele/mysql,segmentio/mysql,helight/helight_code,yyljlyy/mysql,helight/helight_code,joshuaprunier/mysql,springning/mysql,aperera/mysql,bookerzzz/mysql,rlowe/mysql