由于Group By，每日平均值无法正确计算

Question

我有以下SQL，我试图获得总计数超过一个月的每日平均值。

var result = selectInfo.SelectInfoByName("info").Result;

随着上面的数据运行，我得到36行（我的计数）的输出，我将其除以31（天），并且预计每日平均值为1.161，但是我的每行平均输出为.032258（我已经确定是1.16 / 36）。非聚合列位于Group By中，但是以某种方式偏离了每日平均值。

如果我只按计算的平均值SELECT A.BUSINESS_UNIT, A.INV_ITEM_ID, C.MFG_ID, C.MFG_ITM_ID, A.ADJUST_TYPE, A.QTY_BASE, A.UNIT_MEASURE_STD, A.DT_TIMESTAMP, B.DESCR254_MIXED, A.TRANSACTION_GROUP, (CONVERT(CHAR(10),A.TRANSACTION_DATE,121)), A.DEPTID, B.PRICE_LIST, A.DESTIN_GL_BU, A.QTY_BASE* B.PRICE_LIST, (COUNT(*) * 1.0 / 31 ) AS 'Daily Average' FROM PS_TRANSACTION_INV A, (PS_PURCH_ITEM_ATTR B LEFT OUTER JOIN PS_ITEM_MFG C ON B.SETID = C.SETID AND B.INV_ITEM_ID = C.INV_ITEM_ID ), PS_CM_ACCTG_DIST_D D WHERE ( A.BUSINESS_UNIT = '11MMS' AND A.INV_ITEM_ID = B.INV_ITEM_ID AND C.PREFERRED_MFG = 'Y' AND A.TRANSACTION_DATE >= '05-01-2018' AND A.TRANSACTION_DATE <= '05-31-2018' AND A.BUSINESS_UNIT = D.BUSINESS_UNIT AND A.INV_ITEM_ID = D.INV_ITEM_ID AND D.TRANSACTION_GROUP = A.TRANSACTION_GROUP AND A.INV_ITEM_ID = '1') GROUP BY A.BUSINESS_UNIT, A.INV_ITEM_ID, C.MFG_ID, C.MFG_ITM_ID, A.ADJUST_TYPE, A.QTY_BASE, A.UNIT_MEASURE_STD, A.DT_TIMESTAMP, B.DESCR254_MIXED, A.TRANSACTION_GROUP, (CONVERT(CHAR(10),A.TRANSACTION_DATE,121)), A.DEPTID, B.PRICE_LIST, A.DESTIN_GL_BU, A.QTY_BASE* B.PRICE_LIST 运行查询，那么我得到正确的每日平均值1.161，所以我知道它与Group By有关。提前谢谢！

修改

运行此查询     (COUNT(*) * 1.0 / 31 ) AS 'Daily Average' 产生1.161的正确结果，就在我将其添加到上面的查询中时，我的结果不正确。这就是我想在主查询中模仿的内容。

Answer 1

当您按所有列添加分组时，count将始终为1，从而得到结果。

最简单的方法就是将第二个查询作为子查询添加到主查询中，然后就可以丢失该组，如下所示：

SELECT A.BUSINESS_UNIT, A.INV_ITEM_ID, C.MFG_ID, C.MFG_ITM_ID, 
 A.ADJUST_TYPE, A.QTY_BASE, A.UNIT_MEASURE_STD,
 A.DT_TIMESTAMP, B.DESCR254_MIXED, A.TRANSACTION_GROUP, 
 (CONVERT(CHAR(10),A.TRANSACTION_DATE,121)), A.DEPTID, B.PRICE_LIST, 
 A.DESTIN_GL_BU,  A.QTY_BASE* B.PRICE_LIST,  
 (SELECT COUNT(*) * 1.0 / 31
     FROM PS_TRANSACTION_INV A, (PS_PURCH_ITEM_ATTR B LEFT OUTER JOIN
      PS_ITEM_MFG C ON  B.SETID = C.SETID AND B.INV_ITEM_ID = C.INV_ITEM_ID ), 
      PS_CM_ACCTG_DIST_D D 
     WHERE ( A.BUSINESS_UNIT = '11MMS' 
      AND A.INV_ITEM_ID = B.INV_ITEM_ID 
      AND C.PREFERRED_MFG = 'Y' 
      AND A.TRANSACTION_DATE >= '05-01-2018' 
      AND A.TRANSACTION_DATE <= '05-31-2018' 
      AND A.BUSINESS_UNIT = D.BUSINESS_UNIT 
      AND A.INV_ITEM_ID = D.INV_ITEM_ID 
      AND D.TRANSACTION_GROUP = A.TRANSACTION_GROUP 
      AND A.INV_ITEM_ID = '1') 
 )  AS 'Daily Average'
FROM PS_TRANSACTION_INV A, (PS_PURCH_ITEM_ATTR B LEFT OUTER JOIN  
 PS_ITEM_MFG C ON  B.SETID = C.SETID AND B.INV_ITEM_ID = C.INV_ITEM_ID ), 
 PS_CM_ACCTG_DIST_D D 
WHERE ( A.BUSINESS_UNIT = '11MMS' 
 AND A.INV_ITEM_ID = B.INV_ITEM_ID 
 AND C.PREFERRED_MFG = 'Y' 
 AND A.TRANSACTION_DATE >= '05-01-2018' 
 AND A.TRANSACTION_DATE <= '05-31-2018' 
 AND A.BUSINESS_UNIT = D.BUSINESS_UNIT 
 AND A.INV_ITEM_ID = D.INV_ITEM_ID 
 AND D.TRANSACTION_GROUP = A.TRANSACTION_GROUP 
 AND A.INV_ITEM_ID = '1')