Computer Science
Assertion. Generally, a join query combines rows from multiple tables having some common column(s) and a joining condition, but not always.
Reason. A Cartesian product is an unrestricted join where all possible combinations of rows from multiple tables are created without any condition on them.
SQL Joins & Grouping
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Answer
(a)
Both Assertion and Reason are true and Reason is the correct explanation of Assertion.
Explanation
In SQL, a join is a query that combines rows from two or more tables based on a specified condition, such as matching values in a common column. However, this matching condition is not always required; for instance, a Cartesian product is an unrestricted join where all possible combinations of rows from multiple tables are generated without any specific condition. This means that every row from one table is combined with every row from another table.
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Related Questions
Assertion. A GROUP BY query can also include functions.
Reason. ALL SQL functions can be used in a GROUP BY query.
Assertion. SQL SELECT query can also fetch rows from multiple tables.
Reason. A join is a query that combines rows from two or more tables.
Assertion. The join, in which columns are compared for equality, is called Equi-join.
Reason. The join queries only produce combined rows from tables having some common column, when compared for equality.
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Reason. The join in which only one of the identical columns (coming from the joined tables) exists, is called a Natural join.