Question

Equality, non-equality, and self-joins are all categorized as inner joins.

a) TRUE
b) FALSE
c) OUTER JOIN
d) CROSS JOIN

Answer 1

Equality, non-equality, and self-joins are not categorized as inner joins. Inner joins involve joining two tables based on a matching condition, such as a common column between them.

Step-by-step explanation:

The statement given in the question is FALSE. Equality, non-equality, and self-joins are not categorized as inner joins. Inner joins refer to joining two tables based on a matching condition, such as a common column between them. Equality and non-equality join conditions are used in WHERE clauses, while self-joins involve joining a table with itself.

For example, consider two tables, A and B, with a common column 'ID'. If we want to retrieve the rows where the ID values in both tables match, we can use an equality join:

SELECT * FROM A INNER JOIN B ON A.ID = B.ID;

On the other hand, if we want to retrieve the rows where the ID values in both tables are different, we can use a non-equality join:

SELECT * FROM A INNER JOIN B ON A.ID <> B.ID;

Self-joins are commonly used when a table needs to be joined with itself, for example, to find related records within the same table.