Oracle SQL Join

What is an Inner Join in Oracle SQL?

• An Inner Join in Oracle SQL is used to combine rows from two tables based on unrelated columns

• An Inner Join in Oracle SQL returns all rows from both tables, even if there is no match between the columns

• An Inner Join in Oracle SQL is used to combine rows from two tables based on a related column, but only returns rows from the first table

• An Inner Join in Oracle SQL is used to combine rows from two or more tables based on a related column between them. It returns only the rows where there is a match between the columns in both tables.

Explain the concept of Outer Join in Oracle SQL.

• An Outer Join in Oracle SQL retrieves all records from both tables, including matching and non-matching rows.

• An Outer Join in Oracle SQL retrieves all records from one table and only the matching records from another table, including all rows from the left table and the matched rows from the right table. If there is no match, NULL values are returned.

• An Outer Join in Oracle SQL retrieves all records from one table and only the matching records from another table, excluding all rows from the left table.

• An Outer Join in Oracle SQL retrieves only the matching records from both tables, excluding non-matching rows.

How does a Self Join work in Oracle SQL?

• A Self Join works in Oracle SQL by joining a table with itself using aliases to differentiate between the two instances of the same table.

• A Self Join works in Oracle SQL by joining two different tables together.

• A Self Join in Oracle SQL involves creating a new table from the existing table.

• A Self Join in Oracle SQL is used to combine data from multiple unrelated tables.

What is a Cross Join in Oracle SQL?

• A Cross Join in Oracle SQL is a type of left join

• A Cross Join in Oracle SQL is a Cartesian product of two tables.

• A Cross Join in Oracle SQL is a type of self join

• A Cross Join in Oracle SQL is a type of inner join

Describe the Natural Join in Oracle SQL.

• The Natural Join in Oracle SQL combines rows from two tables based on columns with the same name and data type.

• The Natural Join in Oracle SQL combines rows based on the primary key of the tables

• Natural Join in Oracle SQL ignores columns with the same name and data type

• Natural Join in Oracle SQL only works with tables that have identical structures

When would you use a Join with Conditions in Oracle SQL?

• When you want to update the joined rows based on specific conditions

• When you want to join tables without any conditions

• When you want to filter the rows being joined based on specific conditions.

• When you want to sort the joined rows based on specific conditions

What is the difference between Inner Join and Outer Join?

• Inner Join is used for combining data from multiple tables, while Outer Join is used for filtering data

• Inner Join combines all rows, while Outer Join only returns matching rows

• Inner Join compares and returns only matching rows, while Outer Join returns all rows with NULLs for non-matching rows.

• Inner Join returns all rows with NULLs for non-matching rows, while Outer Join compares and returns only matching rows

Can you provide an example scenario where a Self Join would be useful?

• Using Self Join to calculate total sales in a retail store

• Hierarchical data like an organization chart where each employee reports to another employee.

• Applying Self Join to filter data based on a specific condition

• Utilizing Self Join to update records in a database table

How is a Cross Join different from other types of joins?

• A Cross Join generates all possible combinations of rows from the tables involved, while other joins only include rows with matching values.

• A Cross Join is a type of outer join, unlike other joins.

• A Cross Join generates a Cartesian product of rows, while other joins use a different method.

• A Cross Join only includes rows with matching values, similar to other joins.

What are the advantages of using a Natural Join?

• Reduces the need for specifying join conditions explicitly and eliminates duplicate columns automatically.

• Increases the complexity of the query

• Requires specifying join conditions explicitly

• Does not eliminate duplicate columns automatically