Is left or right join faster?
LEFT
When the main table (first non-const one in the execution plan) has a restrictive condition (WHERE id =?) and the corresponding ON condition is on a NULL value, the “right” table is not joined — this is when LEFT JOIN is faster.
How do I join two data in SAS?
To merge two or more data sets in SAS, you must first sort both data sets by a shared variable upon which the merging will be based, and then use the MERGE statement in your DATA statement.
When would you use right join in SQL?
When to Use RIGHT JOIN. The RIGHT OUTER JOIN is used when you want to join records from tables, and you want to return all the rows from one table and show the other tables columns if there is a match else return NULL values.
What is difference between MERGE and join in SAS?
Merge and When to Use Them A very common data manipulation task is to bring two or more sets of data together based on a common key. In SQL, this is known as a join. The SAS® DATA step has the MERGE statement that permits the same thing. If you know SQL, you might never look at using MERGE.
What is right join with example?
The RIGHT JOIN selects the common rows as well as all the remaining rows from the right table. Whereas the INNER JOIN selects only the common rows between two tables. The RIGHT JOIN selects the common rows as well as all the remaining rows from the right table.
Should I ever use right join?
The only reason I can think of to use RIGHT OUTER JOIN is to try to make your SQL more self-documenting. You might possibly want to use left joins for queries that have null rows in the dependent (many) side of one-to-many relationships and right joins on those queries that generate null rows in the independent side.
Why right join is required?
The RIGHT OUTER JOIN is used when you want to join records from tables, and you want to return all the rows from one table and show the other tables columns if there is a match else return NULL values.
Can we replace left join with Right join?
Just switch the table positions and use LEFT JOIN instead of RIGHT JOIN and you get the same result. Even from performance standpoint there should be no difference.