?????????MySQL???????????????????β????????????????????mysql????distinct??????????????????????????????????????????distinct????????????ε?????(count(distinct id))?????????distinct???????????????Σ????????????????Σ??????????±?user:

??????distinct?????????????????select distinct name from user????????

?????????????????????????????????????????id??????б??????????????????????????id??name??select distinct name?? id from user

??????select distinct name?? id from user??????mysql???name?? id??ζ??????????????
????????sql????д??select id?? distinct name from user??????mysql????
???????distinct?????????????ε?????
???????????distinct???????????????????????
????????????????????????????????group by??select id?? name from user group by name