Summary
Text Summary
Understanding Joins
A PROC SQL join is a
query that combines tables horizontally (side by side) by combining
rows. The two main types of joins are inner joins and outer joins.
Generating a Cartesian Product
When you specify multiple
tables in the FROM clause but do not include a WHERE statement to
subset data, PROC SQL returns the Cartesian product of the tables.
In a Cartesian product, each row in the first table is combined with
every row in the second table. In all types of joins, PROC SQL generates
a Cartesian product first, and then eliminates rows that do not meet
any subsetting criteria that you have specified.
Using Inner Joins
An inner join combines and displays the rows from the first table that match rows ...
Get SAS Certification Prep Guide, 4th Edition now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.
