别名和组通过SAS PROC SQL语句

Question

我与PROC SQL在SAS的工作和我的PROC SQL查询之一的行为非常奇怪：

我有一个大的数据集（约1万行），其看起来是这样的：

apple_key profit price cost months date  
golden_d  0.03  12  4  3   01/12 
golden_d  0.03  8  0  2   01/12 
granny_s  0.05  15  5  5   02/12 
red_d  0.04  13  0  1   01/12 
golden_d  0.02  1  2  12   03/14 

在我运行下面的查询这组数据：

%let picking_date = 01/12; /* I simplify here - this part of my code definitely works */ 

proc sql; 
    CREATE TABLE output AS 
    SELECT 
     (CASE apple_key 
       WHEN "golden_d" THEN 1 
       WHEN "granny_s" THEN 2 
       WHEN "red_d" THEN 3 
     END) AS apple_id, 
     apple_key AS apple_name, 
     (CASE WHEN cost= 0 THEN 0 
      ELSE 1 
     END) AS cost_flag, 
     (CASE 
      WHEN CEIL(months/2) < 5 THEN CEIL(months/2) 
      ELSE 5 
     END) AS age, 
     "McDonalds" as farm, 
     sum(profit*price)/sum(price) as price_weighted_profit 
    FROM input_table 
    WHERE date = "&picking_date."d 
     AND price > cost 
     AND cost >= 0 
     AND cost >= 0 
    GROUP BY apple_id, apple_name, cost_flag, age, farm 
    ; 
run; 

当我运行此我GROUP BY声明不起作用。我为单个组获得了一堆条目 （其中apple_id，apple_name，cost_flag，年龄和农场都是相同的，但是我的聚合不起作用）。

但是，当我分别运行GROUP BY（如下所示）时，一切正常。我为每个组获得一个具有“价格加权利润”的条目：

proc sql; 
    CREATE TABLE output_tmp AS 
    SELECT 
     (CASE apple_key 
       WHEN "golden_d" THEN 1 
       WHEN "granny_s" THEN 2 
       WHEN "red_d" THEN 3 
     END) AS apple_id, 
     apple_key AS apple_name, 
     (CASE WHEN cost= 0 THEN 0 
      ELSE 1 
     END) AS cost_flag, 
     (CASE 
      WHEN CEIL(months/2) < 5 THEN CEIL(months/2) 
      ELSE 5 
     END) AS age, 
     "McDonalds" as farm 
    FROM input_table 
    WHERE date = "&picking_date."d 
     AND price > cost 
     AND cost >= 0 
     AND cost >= 0 
    ; 

    CREATE TABLE output AS 
    SELECT 
     apple_id, 
     apple_name, 
     cost_flag, 
     age, 
     farm, 
     sum(profit*price)/sum(price) as price_weighted_profit 
    FROM output_tmp 
    GROUP BY apple_id, apple_name, cost_flag, age, farm 
    ; 
quit; 

为什么会发生这种情况？我该如何解决它？这是让我有点疯狂......谢谢前面的帮助

Answer 1

它不起作用，因为group by没有把总和（利润*价格）/总和（价格）语句作为聚合函数。它没有做到这一点，因为像年龄的别名，cost_flag等

反正下面是正确的查询： -

Proc sql; 
    CREATE TABLE output AS 
    SELECT 
      apple_id, 
      apple_name, 
      cost_flag, 
      age, 
      farm, 
      sum(profit*price)/sum(price) as price_weighted_profit 
     FROM 
     (
     SELECT 
      (CASE apple_key 
        WHEN "golden_d" THEN 1 
        WHEN "granny_s" THEN 2 
        WHEN "red_d" THEN 3 
      END) AS apple_id, 
      apple_key AS apple_name, 
      (CASE WHEN cost= 0 THEN 0 
       ELSE 1 
      END) AS cost_flag, 
      (CASE 
       WHEN CEIL(months/2) < 5 THEN CEIL(months/2) 
       ELSE 5 
      END) AS age, 
      "McDonalds" as farm 
     FROM input_table 
     WHERE date = "&picking_date."d 
      AND price > cost 
      AND cost >= 0 
      AND cost >= 0 

     ) a 
     GROUP BY apple_id, apple_name, cost_flag, age, farm; 
     quit; 

让我知道如果您有任何疑问

Answer 2

经验法则： - 每当您在select子句中使用任何聚合函数，其余列应该是group by的一部分。在您发布的问题中，您发布的申请是总和（利润*价格）/总和（价格），但是没有导致问题的组。

Proc sql; 
    CREATE TABLE output AS 
     SELECT 
      (CASE apple_key 
        WHEN "golden_d" THEN 1 
        WHEN "granny_s" THEN 2 
        WHEN "red_d" THEN 3 
      END) AS apple_id, 
      apple_key AS apple_name, 
      (CASE WHEN cost= 0 THEN 0 
       ELSE 1 
      END) AS cost_flag, 
      (CASE 
       WHEN CEIL(months/2) < 5 THEN CEIL(months/2) 
       ELSE 5 
      END) AS age, 
      "McDonalds" as farm, 
      sum(profit*price)/sum(price) as price_weighted_profit 
     FROM input_table 
     WHERE date = "&picking_date."d 
      AND price > cost 
      AND cost >= 0 
      AND cost >= 0  
     GROUP BY apple_id, apple_name, cost_flag, age, farm; 
     quit; 

Answer 3

我怀疑发生了什么是remerging。 SAS PROC SQL接受这样的代码：

proc sql; 
    select a.*, count(*) 
    from a; 

这并不汇总数据。相反，它将整个计数放在每一行上。换句话说，如果select中的密钥与group by不完全匹配，则根据group by密钥计算聚合函数，但结果会放在单独的行上。其他数据库使用窗口函数的子集来完成此操作。

在你的情况下，淹没并不明显。我认为存在关键的困惑，因为您在select中使用与原始数据中相同的名称。我的建议是更改别名，使其明确无误，并确保group by中的密钥是明确的。