您必须为此使用副作用变量
SELECt profilename, nameFROM( SELECt m.profilename, s.name, @r:=case when @g=m.profilename then @r+1 else 1 end r, @g:=m.profilename FROM (select @g:=null,@r:=0) n cross join menus m left join menuitems s on m.menuid = s.menuid) XWHERe r <= 5
