How do you make an outer join in Oracle?

To write a query that performs an outer join of tables A and B and returns all rows from A (a left outer join), use the LEFT [ OUTER ] JOIN syntax in the FROM clause, or apply the outer join operator (+) to all columns of B in the join condition in the WHERE clause.

What is the use of (+) in Oracle?

In Oracle, (+) denotes the “optional” table in the JOIN.

How does left outer join work in Oracle?

A LEFT OUTER JOIN performs an inner join of two tables (supposed table A which writes before the join keyword and table B which writes after the join keyword in the SQL statement ) based on the condition specified after the ON keyword. It returns all rows from the table A as well as the unmatched rows from the table B.

Why we use outer join in SQL?

We use the SQL OUTER JOIN to match rows between tables. We might want to get match rows along with unmatched rows as well from one or both of the tables. We have the following three types of SQL OUTER JOINS. Let’s explore each of SQL Outer Join with examples.

Does left outer join remove duplicates?

Avoiding Duplicates Again, if we perform a left outer join where date = date, each row from Table 5 will join on to every matching row from Table 4. However, in this case, the join will result in 4 rows of duplicate dates in the joined DataSet (see Table 6).

What is difference between left join and left outer join?

There really is no difference between a LEFT JOIN and a LEFT OUTER JOIN. Both versions of the syntax will produce the exact same result in PL/SQL. Some people do recommend including outer in a LEFT JOIN clause so it’s clear that you’re creating an outer join, but that’s entirely optional.

Why we use SQL joins?

The SQL Joins clause is used to combine records from two or more tables in a database. A JOIN is a means for combining fields from two tables by using values common to each. INNER JOIN − returns rows when there is a match in both tables.

When we use join in SQL?

A SQL Join statement is used to combine data or rows from two or more tables based on a common field between them.

What happens if you do not use outer join in Oracle?

If you do not, then Oracle Database will return only the rows resulting from a simple join, but without a warning or error to advise you that you do not have the results of an outer join. The (+) operator does not produce an outer join if you specify one table in the outer query and the other table in an inner query.

What is Oracle join in SQL?

Oracle join is used in queries to join two or more tables, columns or views based on the values of related columns of both the tables.

What is a left join in SQL?

The left join returns all rows from the left table with the matching rows if available from the right table. If there is no matching row found from the right table, the left join will have null values for the columns of the right table: The following Venn diagram illustrates the left join:

What is the use of RIGHT OUTER JOIN in SQL?

The RIGHT OUTER JOIN returns contain all rows from the RIGHT table (according to the specified in ON condition) and from the other table only those rows where the joined condition is true. The RIGHT OUTER JOIN keyword, use as RIGHT JOIN in some other databases.