直接加${if(AND(len(class) == 0,len(su)==0),"and COURSE = 'English' and grade between '60'and '80'","")}
${if(AND(len(class) == 0,len(su)==0),"and COURSE = 'English' and grade >=60 and grade <80","")}
判断 条件里有两个参数。你要写哪个啊?
${if(AND(len(class) == 0,len(su)==0),"and COURSE = 'English' and grade < 80","")}
${if(AND(len(class) == 0,len(su)==0),"and COURSE = 'English' and grade <'80'","")}