Question

In an SQL query of two tables, which SQL keyword indicates that we want data from all the rows of one table to be included in the result, even if the row does not correspond to any data in the other table?

a) LEFT JOIN

b) RIGHT JOIN

c) INCLUDE

d) Both LEFT JOIN and RIGHT JOIN are correct

Answer 1

In SQL querying, data from all rows of one table is included using either LEFT JOIN or RIGHT JOIN, depending on whether the table in question is on the left or right side of the join respectively.

Correct option is d) Both LEFT JOIN and RIGHT JOIN are correct

Step-by-step explanation:

In an SQL query of two tables, when we want data from all the rows of one table to be included in the results, even if there isn't a corresponding row in the other table, we use either a LEFT JOIN or a RIGHT JOIN. A LEFT JOIN includes all rows from the left table specified in the LEFT JOIN clause, regardless of whether there are matching rows in the right table. Conversely, a RIGHT JOIN includes all rows from the right table, irrespective of matches in the left table. So when joining Table A (left) and Table B (right), a LEFT JOIN will include all rows from Table A, while a RIGHT JOIN will include all rows from Table B.

Therefore, the correct answers are d) Both LEFT JOIN and RIGHT JOIN, depending on the tables' positions in the query.