Merge If a; data Temp1_2; merge ICF(in=a) DM(in=b); by cn dn; if a; run; <Sql实现方法> proc sql ; create table Temp1_1 as select distinct a.*,b.BIRTHDAT from ICF as a left join DM as b on a.cn =b.cn and a.dn =b.dn ; quit; Merge If b; data Temp1_2; merge ...
坦白来讲,同时给我 merge by 和 proc sql,我会选 sql。上面的输出数据集是没问题的,以 A 中 id 作为 left join 的 key variable,同时搜索 B 中有相同 id 取值的行,进行左连接横向匹配合并。A 中无 weight 变量,故 A 的部分观测的 weight 为缺失。 merge by Data dummy; Merge A(IN= X) B(IN= ...
This paper compares two methods for accomplishing a many- to-many match-merge with The SAS System(R), a DATA STEP method and a PROC SQL method. (1) The DATA STEP method uses a technique called "match-crossing" by Aster & Seidman in their book Professional SAS Program- ming Secrets. ...
PROC SQL与MERGE 例: 中国队 美国队 使用merge时:如果两个数据集变量名相同,则以后面的数据集为准覆盖前面的数据集的变量。而如果不同,则像下面一样,依旧以后表为准,依次连接前表。 1DATA PINGPANG;2MERGE CHINA USA;3RUN; #output 使用SQL时:在SQL中应具体匹配到关键字,然后会从笛卡儿积中选取两个表中...
Editor's Note: In addition to the many resources listed below, I'm adding this video tutorial. At just under 7 minutes, it walks you through the steps of merging data sets in SAS using PROC SQL: DATA step merge and SQL join handles duplicate key values differently, which is described an...
merge by Data dummy; Merge A(IN= X) B(IN= Y); by ID; If X; run; proc print; run; 输出数据集完全一样,从结果上来看,二者等效。 细节 然而,你留意看 SAS log 的话,proc sql 会有这样的 warning,而 merge by 就不会有这个 warning。
前几节我们介绍了 SELECT 语句的简单查询用法。事实上,SELECT 查询语句本身作为一种表达式(sql expression),自然可以嵌套在其他语句中,SELECT 语句的这种用法被称为子查询(Subqueries)。 子查询可以应用在 PROC SQL 的多个地方,下面介绍一些常见的用法。 插入观测 ...
In SQL, this is commonly done by specifying the desired columns instead of using *, which selects all: PROC SQL; CREATE TABLE Output_table AS SELECT Name, Gender FROM Input_table; QUIT; In a DATA step, this can be done by dropping the columns the user isn't interested in: DATA ...
Occasionally, an application problem comes along where the SQL procedure is either better suited or easier to use than other more conventional DATA and/or PROC step methods. As each situation presents itself, PROC SQL should be examined to see if its use is warranted for the task at hand. ...
PROC SQL is quicker on the real large ones that are sorted. This means that the SQL proc utilizes the sort index and only reads the records that it needs. The data step (merge) will read all the records and then only use the ones it needs. So if you plan to read through the ...