${if(rylx != '筛选条件:无',if(len(renyuan) == 0,"","and renyuan = '" + renyuan + "'"),'')}

${if( or(rylx != "筛选条件:无",len(renyuan) = 0),"","and renyuan = '" + renyuan + "'")}

 另外如果里面要套一层的话，直接if 就行了，不用再写一遍 ${}

if 语句的语法，如果某某条件=True ，则...，否则...

如果rylx != '筛选条件:无',${if(len(renyuan) == 0 是一个合并的条件，那么

${if((rylx != '筛选条件:无' and ${if(len(renyuan) == 0),"","and renyuan = '" + renyuan + "'")},'')}

但其实我觉得rylx != '筛选条件:无' 有点多余，因为已经有一个参数条件了

${if(${if(len(renyuan) == 0,"","and renyuan = '" + renyuan + "'")},'')}

最后还是根据自己的情况来，注意语法就行