MySQL查询当月销售额按月和前一年按月销售额

Question

我怎样才能逐月获得去年的净销售额？
  我试图通过相关的增加/减少百分比报告当前月份的销售信息。

select date_format(sdate,'%M-%Y') as sdate,     
    sum(netsales) as 'netsales',  
    from repsoft.daily  
    where scode=1234 and year(sdate)=year('2016-06-01')  
    group by month(sdate)  
    order by month(sdate);  

Answer 1

为什么不按年份分组呢？

select date_format(sdate,'%M-%Y') as sdate,     
    sum(netsales) as 'netsales',  
    from repsoft.daily  
    where scode=1234 and year(sdate)=year('2016-06-01')  
    group by year(sdate), month(sdate)  
    order by year(sdate), month(sdate);