+ t0 ?3 a- g8 t7 N0 Eselect distinct classname from practice where coursename='网络营销' order by code---------------- , W, o: N/ L4 t! }! {2 i“如果指定了 SELECT DISTINCT,那么 ORDER BY 子句中的项就必须出现在选择列表中。”& H; \1 {1 {. E
" d( @ l' d9 w3 G$ ~) a' s改成这种 # b0 u0 I. k( d" E; H8 O1 X/ h4 @select classname from(select max(code)as code ,classname from practice where coursename='网络营销' group by classname)a order by code