排序并去除重复

排序用group by

去除重复用max(expr)

SELECT ed.ID,ed.`NAME`,ed.RATIO,max(e.DLDT),e.TAE,e.TAE/ed.RATIO 
from e_eledata e , e_elemeterhead ed 
where e.E_ELEMETERHEAD_ID = ed.ID  
and ed.`STATUS` = '0'
group by ed.ID,ed.`NAME`,ed.RATIO	;

自己常用的SQL查询语句