我想select 3 个 count (based on different conditions)  in one query
 下面是我的code, 每个select单独run就对,加上union就run不出来了
Select datepart(y,mydate), datepart(mon, mydate), count(distinct link) as entire  From lemon
where link like '%shop.lemon.com/checkout/spk/confirmation.jsp%' 
group by datepart(y,mydate), datepart(mon,mydate)
order by datepart(y,mydate), datepart(mon,mydate)
Union
Select datepart(y,mydate), datepart(mon, mydate), count(distinct link) as Canada  From lemon
where link like '%shop.lemon.com/checkout/spk/confirmation.jsp%'and countrycode = '164'
group by datepart(y,mydate), datepart(mon,mydate)
order by datepart(y,mydate), datepart(mon,mydate)
Union 
Select datepart(y,mydate), datepart(mon, mydate), count(distinct link) as USA  From lemon
where link like '%shop.lemon.com/checkout/spk/confirmation.jsp%'and countrycode = '840'
group by datepart(y,mydate), datepart(mon,mydate)
order by datepart(y,mydate), datepart(mon,mydate)