拆成两句
${if(len(begin)==0,"","and to_char(date,'yyyy/MM') >='"+begin+"'")} ${if(len(end)==0,"","and to_char(date,'yyyy/MM') <='"+end+"'")}
${if(len(begin)==0||len(end)==0,"","and to_char(date,'yyyy/MM') betwwen '"+begin+"' and '"+end+"'")}
https://help.fanruan.com/finereport/doc-view-420.html 这里有