Inner join creates a dataset that contains records that have matching values from both the tables. For example, we have a dataset A that contains customer information and a dataset B that contains credit card details. To get the credit card details of customers in dataset A, let us create dataset C
PROC SQL;
CREATE TABLE C AS
SELECT A.*, B.CC_NUM
FROM CUSTOMER A, CC_DETAILS B
WHERE A.CUSTOMERID=B.CUSTOMERID
QUIT;
Dataset C will have only matching observations from both the datasets.