Question

    In SQL, which type of JOIN will return all rows from the

    left table and the matching rows from the right table, filling with NULLs where there is no match?
    A INNER JOIN Correct Answer Incorrect Answer
    B LEFT JOIN Correct Answer Incorrect Answer
    C RIGHT JOIN Correct Answer Incorrect Answer
    D FULL JOIN Correct Answer Incorrect Answer
    E CROSS JOIN Correct Answer Incorrect Answer

    Solution

    A LEFT JOIN in SQL returns all records from the left table (the first table specified in the query) and the matched records from the right table. If there is no match, the result will contain NULL values in columns from the right table. This join type is particularly useful in scenarios where you need to keep all data from the primary table, even if corresponding records do not exist in the related table. It is commonly used when performing analyses requiring comprehensive data from one table while optionally pulling related data from another. The other options are incorrect because: • Option 1 (INNER JOIN) only returns rows with matching values in both tables. • Option 3 (RIGHT JOIN) returns all rows from the right table, not the left. • Option 4 (FULL JOIN) includes all matching and non-matching rows from both tables. • Option 5 (CROSS JOIN) returns the Cartesian product without any filtering on matching keys.

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