左加入 returns 个空格

Question

我执行了左连接，其中左 table 有 500,000 个观察值。在某些情况下，左连接对于 Business_Line = "Retail" 是成功的，而下一个观察结果留空，这是为什么？

我使用的代码：

proc sql;
create table joined2 as
select a.*
      ,b.Join1
      ,b.Join2
      ,b.Join3
from joined as a
left join Sasdata.Assumptions as b
on a.Business_Line = b.Business_Line;
quit;

两个table长得像

data joined;
input Business_Line $;
datalines;
Retail
Retail
Retail
Business
Business
;
run;

要加入的 table 看起来像

data sasdata.assumptions;
input Business_Line $ Join1 Join2 Join3;
datalines;
Retail 10% 10% 10%
Business 20% 10% 5%
;
run;

当前结果 table 看起来像

 business_line join1 join2 join3
 Retail 10% 10% 10%
 Retail . . .
 Business 20% 10% 5%
 Business . . .

Answer 1

示例代码未演示该问题。

确实，当实际 business_lines 值为 'Retail' 或 Business 时，join1-join3 的缺失值不会发生。您得到的结果是 3x1 行的 Retail 和 2x1 行的 Business。

当左侧 table 中的连接键在右侧 table 中没有相应的匹配项时，就会出现缺失值。如果变量被格式化，这可能似乎在 SAS 中发生。

假设 business_line 是一个具有格式化值

的整数

proc format;
  value line
    101 = 'Retail'
    102 = 'Retail'
    103 = 'Retail'
    201 = 'Business'
    202 = 'Business'
  ;

更新数据 business_line

data joined;
input Business_Line;
format Business_Line line.;
datalines;
101
102
102
201
202
run;    

data assumptions;
input Business_Line Join1 Join2 Join3;
format Business_Line line.;
datalines;
101 10 10 10
201 20 10  5
run;

具有一些不匹配的基础值的联接

proc sql;
create table joined2 as
select a.*
      ,b.Join1
      ,b.Join2
      ,b.Join3
from joined as a
left join Assumptions as b
on a.Business_Line = b.Business_Line;
quit;

options nocenter; ods listing;
proc print data=joined2;
run;

结果显示缺失值

       Business_
Obs      Line       Join1    Join2    Join3

 1     Retail         10       10       10
 2     Retail          .        .        .
 3     Retail          .        .        .
 4     Business       20       10        5
 5     Business        .        .        .

左加入 returns 个空格

Left join returns blanks

join

sas

left-join

sas-studio