${if(len(y)==0,"",if(m=="01","and substr(DATETIME,1,4)='"+(y-1)+"'","and substr(DATETIME,1,4)='"+y+"'"))}
${if(len(m)==0,"",if(m=="01","and substr(DATETIME,6,2)='12'","and to_number(substr(DATETIME,6,2))=to_number('"+m+"')-1"))}
将年份和月份合并到一起再进行减一