关于两个测试数据集匹配合并,不同连接方式的结果 横向合并: inner join:只对第一个表和第二个表共有的行匹配结果,若包含重复值,采用笛卡尔交集组合 left join:在inner join的基础上保留,主表的其他观测 right join:在inner join的基础上保留,副表的其他观测,但是非共有的观测行,无法显示匹配变量
PROC SQL is a powerful yet still overlooked tool within our SAS arsenal. PROC SQL can create tables, sort and summarize data, and join/merge data from multiple tables and in-line views. The SELECT statement with the CASEWHEN clause can conditionally process the data like the IF-THEN-ELSE ...
Full Join、On、 Where区别和用法，不用我说其实前面的这些基本SQL语法各位攻城狮基本上都用过。
总结起来,使用proc sql join时,不可以使用OR语句来指定关联条件,而是应该使用AND语句来连接多个关联条件。
from where 和inner join +on的作用一致 inner join +on是为了和left/right join on 相统一。 1proc sql;2title'self join';3selecta.gtone,b.shen4frommysas.ifthen1 a,mysas.ifthen1 b5wherea.date=b.date;6quit; 用别名可以实现自身与自身的查询。
from where 和inner join +on的作用一致 inner join +on是为了和left/right join on 相统一。 1proc sql;2title'self join';3selecta.gtone,b.shen4frommysas.ifthen1 a,mysas.ifthen1 b5wherea.date=b.date;6quit; 用别名可以实现自身与自身的查询。
from where 和inner join +on的作用一致 inner join +on是为了和left/right join on 相统一。 1proc sql;2title'self join';3selecta.gtone,b.shen4frommysas.ifthen1 a,mysas.ifthen1 b5wherea.date=b.date;6quit; 1. 2. 3. 4. 5.
简单来说 union是纵向合并两张表，合并后的表更长了 join是横向合并两张表，合并后的表更宽了
SYNTAX – MERGING TWO TABLES PROC SQL; CREATE TABLE PATIENT_INFO3A AS SELECT B.*, A.HOSPITAL_ADMISSION_DATE FROM HOSPITAL_ADMISSION A RIGHT JOIN PATIENT_DEMOGRAPHICS B ON A.PATIENT_ID EQ B.PATIENT_ID WHERE HOUSEHOLD_IINCOME GT 0; QUIT; RESULT TABLE: PATIENT_INFO3A OBS # 1 2 3 4 5 ...
returned from the table on the right side of the statement, in this case the remdates tables. Some databases require a slightly different syntax for an outer join. Oracle uses the following syntax for their outer joins: Proc SQL: create table merged as ...