任何其他方式使查詢更短？

Question

select A.regYear, A.regMonth, isnull(A.regCount,0), isnull(B.regCount,0), isnull(C.regCount,0), isnull(D.regCount,0), 
isnull(E.regCount,0), isnull(F.regCount,0), 
isnull(G.regCount,0),isnull(H.regCount,0),isnull(I.regCount,0),isnull(J.regCount,0), 
isnull(K.regCount,0),isnull(L.regCount,0),isnull(M.regCount,0),isnull(N.regCount,0), 
isnull(O.regCount,0),isnull(P.regCount,0),isnull(Q.regCount,0) 
from (

select Year(reg_date) as regYear, Month(reg_Date) as RegMonth, count(*) as RegCount 
from dailyregistration 
group by Year(reg_date) , Month(reg_Date)) A 

left join 

(select Year(reg_date) as regYear, Month(reg_Date) as RegMonth, 
count(1) as RegCount from dailyregistration 
where datediff(day, reg_date, reg_activationdate) < 0 
group by Year(reg_date) , Month(reg_Date)) B on A.RegYear = B.regYear and A.RegMonth = B.RegMonth 

left join 

(select Year(reg_date) as regYear, Month(reg_Date) as RegMonth, 
count(1) as RegCount from dailyregistration 
where datediff(day, reg_date, reg_activationdate) = 0 
group by Year(reg_date) , Month(reg_Date)) C on A.RegYear = C.regYear and A.RegMonth = C.RegMonth 

left join 

(select Year(reg_date) as regYear, Month(reg_Date) as RegMonth, 
count(1) as RegCount from dailyregistration 
where datediff(day, reg_date, reg_activationdate) = 1 
group by Year(reg_date) , Month(reg_Date)) D on A.RegYear = D.regYear and A.RegMonth = D.RegMonth 

left join 

(select Year(reg_date) as regYear, Month(reg_Date) as RegMonth, 
count(1) as RegCount from dailyregistration 
where datediff(day, reg_date, reg_activationdate) = 2 
group by Year(reg_date) , Month(reg_Date)) E on A.RegYear = E.regYear and A.RegMonth = E.RegMonth 

left join 

(select Year(reg_date) as regYear, Month(reg_Date) as RegMonth, 
count(1) as RegCount from dailyregistration 
where datediff(day, reg_date, reg_activationdate) = 3 
group by Year(reg_date) , Month(reg_Date)) F on A.RegYear = F.regYear and A.RegMonth = F.RegMonth 

left join 

(select Year(reg_date) as regYear, Month(reg_Date) as RegMonth, 
count(1) as RegCount from dailyregistration 
where datediff(day, reg_date, reg_activationdate) = 4 
group by Year(reg_date) , Month(reg_Date)) G on A.RegYear = G.regYear and A.RegMonth = G.RegMonth 


left join 

(select Year(reg_date) as regYear, Month(reg_Date) as RegMonth, 
count(1) as RegCount from dailyregistration 
where datediff(day, reg_date, reg_activationdate) = 5 
group by Year(reg_date) , Month(reg_Date)) H on A.RegYear = H.regYear and A.RegMonth = H.RegMonth 

left join 

(select Year(reg_date) as regYear, Month(reg_Date) as RegMonth, 
count(1) as RegCount from dailyregistration 
where datediff(day, reg_date, reg_activationdate) = 6 
group by Year(reg_date) , Month(reg_Date)) I on A.RegYear = I.regYear and A.RegMonth = I.RegMonth 

left join 

(select Year(reg_date) as regYear, Month(reg_Date) as RegMonth, 
count(1) as RegCount from dailyregistration 
where datediff(day, reg_date, reg_activationdate) = 7 
group by Year(reg_date) , Month(reg_Date)) J on A.RegYear = J.regYear and A.RegMonth = J.RegMonth 

left join 

(select Year(reg_date) as regYear, Month(reg_Date) as RegMonth, 
count(1) as RegCount from dailyregistration 
where datediff(day, reg_date, reg_activationdate) = 14 
group by Year(reg_date) , Month(reg_Date)) K on A.RegYear = K.regYear and A.RegMonth = K.RegMonth 

left join 

(select Year(reg_date) as regYear, Month(reg_Date) as RegMonth, 
count(1) as RegCount from dailyregistration 
where datediff(day, reg_date, reg_activationdate) = 21 
group by Year(reg_date) , Month(reg_Date)) L on A.RegYear = L.regYear and A.RegMonth = L.RegMonth 

left join 

(select Year(reg_date) as regYear, Month(reg_Date) as RegMonth, 
count(1) as RegCount from dailyregistration 
where datediff(day, reg_date, reg_activationdate) = 28 
group by Year(reg_date) , Month(reg_Date)) M on A.RegYear = M.regYear and A.RegMonth = M.RegMonth 
left join 

(select Year(reg_date) as regYear, Month(reg_Date) as RegMonth, 
count(1) as RegCount from dailyregistration 
where datediff(day, reg_date, reg_activationdate) > 28 
group by Year(reg_date) , Month(reg_Date)) N on A.RegYear = N.regYear and A.RegMonth = N.RegMonth 


left join 

(select Year(reg_date) as regYear, Month(reg_Date) as RegMonth, count(*) as RegCount 
from dailyregistration 
where reg_activationdate is not null 
group by Year(reg_date) ,Month(reg_Date)) O on A.RegYear = O.regYear and A.RegMonth = O.RegMonth 

left join 

(select Year(reg_date) as regYear, Month(reg_Date) as RegMonth, count(*) as RegCount 
from dailyregistration 
where reg_activationdate is null 
group by Year(reg_date) ,Month(reg_Date)) P on A.RegYear = P.regYear and A.RegMonth = P.RegMonth 

left join 

(select Year(prt_completed) as regYear, Month(prt_completed) as RegMonth, count(*) as RegCount 
from dailyPortOut 
where prt_status = 'COMPLETED' 
group by Year(prt_completed) ,Month(prt_completed)) Q on A.RegYear = Q.regYear and A.RegMonth = Q.RegMonth 

order by A.regYear, A.regMonth 

Answer 1

看起來您正在創建一個可以完成三件事的報表。 1：比較登記與激活的天數，從0到7（不知道爲什麼datediff會小於0，但可能是錯誤檢查？），14天，21天，28天和28天或更多。 2：報告激活或未激活的註冊總數，以及3：...不確定子查詢Q應該由「端口出日期」報告。

爲什麼不第一階段的數據，一拉：

 
create table #t 
(regYear smallint, regMonth smallint 
, reg_activationDate dateTime, dayDiff smallint 
) 
insert #t select year(reg_date), month(reg_date) 
, reg_activationDate, datediff(day, reg_date, reg_activationDate) 
from dailyregistration 

然後做一個更簡單的交叉表查詢：

 
select regYear, regMonth, sum(case when dayDiff < 0 then 1 else 0 end) [lt 0] 
, sum (case when dayDiff = 0 then 1 else 0 end) [eq 0] 
, ... 
, sum(case when dayDiff > 28 then 1 else 0 end) [gt 28] 
, sum(case when reg_activationDate is not null then 1 else 0 end) [Total Activated] 
, sum(case when reg_activationDate is null then 1 else 0 end) [Total Not Activated] 
from #t 
group by regYear, regMonth 

仍不能確定最終的狀態。

Answer 2

這是公共表表達式使用一個最好的例子：

WITH daily_reg AS (
    SELECT YEAR(dr.reg_date) as regYear, 
     MONTH(dr.reg_Date) as RegMonth, 
     COUNT(*) as RegCount 
    FROM DAILYREGISTRATION dr 
GROUP BY YEAR(dr.reg_date) , MONTH(dr.reg_Date)), 
    daily_portout AS (
    SELECT YEAR(d.reg_date) as regYear, 
     MONTH(d.reg_Date) as RegMonth, 
     COUNT(*) as RegCount 
    FROM DAILYPORTOUT d 
    WHERE d.prt_status = 'COMPLETED' 
GROUP BY YEAR(d.prt_completed), MONTH(d.prt_completed)) 
    SELECT a.regyear, 
      a.regmonth, 
      ISNULL(a.regCount,0), 
      ISNULL(b.regCount,0), 
      ISNULL(d.regCount,0), 
      ISNULL(d.regCount,0), 
      ISNULL(e.regCount,0), 
      ISNULL(f.regCount,0), 
      ISNULL(g.regCount,0), 
      ISNULL(h.regCount,0), 
      ISNULL(i.regCount,0), 
      ISNULL(j.regCount,0), 
      ISNULL(k.regCount,0), 
      ISNULL(l.regCount,0), 
      ISNULL(m.regCount,0), 
      ISNULL(n.regCount,0), 
      ISNULL(o.regCount,0), 
      ISNULL(p.regCount,0), 
      ISNULL(q.regCount,0) 
    FROM daily_reg a 
LEFT JOIN daily_reg b ON b.regyear = a.regyear 
        AND b.regmonth = a.regmonth 
LEFT JOIN daily_reg c ON c.regyear = a.regyear 
        AND c.regmonth = a.regmonth 
LEFT JOIN daily_reg d ON d.regyear = a.regyear 
        AND d.regmonth = a.regmonth 
LEFT JOIN daily_reg e ON e.regyear = a.regyear 
        AND e.regmonth = a.regmonth 
LEFT JOIN daily_reg f ON f.regyear = a.regyear 
        AND f.regmonth = a.regmonth 
LEFT JOIN daily_reg g ON g.regyear = a.regyear 
        AND g.regmonth = a.regmonth 
LEFT JOIN daily_reg h ON h.regyear = a.regyear 
        AND h.regmonth = a.regmonth 
LEFT JOIN daily_reg i ON i.regyear = a.regyear 
        AND i.regmonth = a.regmonth 
LEFT JOIN daily_reg j ON j.regyear = a.regyear 
        AND j.regmonth = a.regmonth 
LEFT JOIN daily_reg k ON k.regyear = a.regyear 
        AND k.regmonth = a.regmonth 
LEFT JOIN daily_reg l ON l.regyear = a.regyear 
        AND l.regmonth = a.regmonth 
LEFT JOIN daily_reg m ON m.regyear = a.regyear 
        AND m.regmonth = a.regmonth 
LEFT JOIN daily_reg n ON n.regyear = a.regyear 
        AND n.regmonth = a.regmonth 
LEFT JOIN daily_reg o ON o.regyear = a.regyear 
        AND o.regmonth = a.regmonth 
LEFT JOIN daily_reg p ON p.regyear = a.regyear 
        AND p.regmonth = a.regmonth 
LEFT JOIN daily_portout dp ON dp.regyear = a.regyear 
          AND dp.regmonth = a.regmonth 
    WHERE DATEDIFF(day, b.reg_date, b.reg_activationdate) < 0 
     AND DATEDIFF(day, c.reg_date, c.reg_activationdate) = 0 
     AND DATEDIFF(day, d.reg_date, d.reg_activationdate) = 1 
     AND DATEDIFF(day, e.reg_date, e.reg_activationdate) = 2 
     AND DATEDIFF(day, f.reg_date, f.reg_activationdate) = 3 
     AND DATEDIFF(day, g.reg_date, g.reg_activationdate) = 4 
     AND DATEDIFF(day, h.reg_date, h.reg_activationdate) = 5 
     AND DATEDIFF(day, i.reg_date, i.reg_activationdate) = 6 
     AND DATEDIFF(day, j.reg_date, j.reg_activationdate) = 7 
     AND DATEDIFF(day, k.reg_date, k.reg_activationdate) = 14 
     AND DATEDIFF(day, l.reg_date, l.reg_activationdate) = 21 
     AND DATEDIFF(day, m.reg_date, m.reg_activationdate) = 28 
     AND DATEDIFF(day, n.reg_date, n.reg_activationdate) > 28 
     AND o.reg_activationdate IS NOT NULL 
     AND p.reg_activationdate IS NULL 
ORDER BY a.regyear, a.regmonth