我的sql有问题，我试图根据年龄组显示用户，将字符串与主键一起附加，但我只希望显示一个值我相信是这样的SELECTusers.gbpfid,users.aid,compresults.total,agegroup.aidASaid2FROMcompresultsINNERJOINcompetitionsONcompetitions.cid=compresults.cidINNERJOINagegroupONagegroup.aid=users.aidINNERJOINusersONcompresults.gbpfid=users.gbpfidWHEREcompetitions.comp