What is the purpose of the JOIN clause in SQL?
Which type of JOIN returns only matching rows from both tables?
Which SQL clause is used to sort the result set in ascending or descending order?
What is the difference between WHERE and HAVING clauses?
What will be the result of this query: SELECT * FROM employees WHERE salary > 50000 AND department = 'IT';
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Which SQL function is used to count non-NULL values in a column?
What does the PRIMARY KEY constraint ensure?
Which of the following SQL wildcards matches any single character?
Which SQL statement is used to delete all records from a table without removing the table structure?
Which aggregate function ignores NULL values by default?
Given a table 'employees' with salary column, which query finds employees earning more than average salary?
What is the difference between CROSS JOIN and INNER JOIN?
Which statement correctly uses aliases in SQL?
For a query with transactions table, which index type is most efficient for WHERE clauses checking transaction_date range?
What is the output of: SELECT COALESCE(NULL, NULL, 'SQL', 'Database');?
In a normalized database following 3NF, which anomaly is prevented?
Which of the following queries demonstrates a self-join correctly?
In a bank database with accounts and transactions tables, to find accounts with transactions greater than 100,000, which clause must follow GROUP BY?
What will be the result of: SELECT 310 in SQL?
A company table has 500K employee records. To find employees with salary > 50,000 efficiently, which strategy is optimal?