MySQL Multiple Choice Answer as soon as possible

1. To create a scheduled event in MySQL that executes only once three hours from now we would use the following syntax: (a) ON SCHEDULE AT CURRENT_TIMESTAMP + INTERVAL 3 HOUR (b) RUN IN INTERVAL 3 HOUR (c) RUN AT CURRENT_TIMESTAMP + INTERVAL 3 HOUR (d) RUN IN 3 HOUR (e) ON SCHEDULE INTERVAL 3 HOUR

2. What can happen if we create a query that DELETEs lots of rows (>1 Million) at once? (a) The DELETE query could lock a lot of rows at once. (b) The DELETE query could block small queries that shouldn't be interrrupted. (c) The DELETE query could fill up the transaction logs. (d) The DELETE query could hog resources unnecessarily. (e) All of the above. (f) None of the above.

3. Which of the following statements causes MySQL to pause for 10 seconds before returning? (a) DELAY(10); (b) SELECT SLEEP(10000); (c) PAUSE(10); (d) SELECT SLEEP(10); (e) PAUSE(10000); (f) DELAY(10000);

4. Which one of the following IODKU (INSERT...ON DUPLICATE KEY UPDATE) clauses will update the count column if attempting to INSERT where the username and login_month already exist: INSERT INTO login_summary (username, login_month, count) VALUES ("Suzanna","2018-11",1) (a) ON DUPLICATE KEY (username, login_month) UPDATE count=count+1; (b) ON DUPLICATE KEY UPDATE count=count+1; (c) ON DUPLICATE KEY UPDATE login_summary SET count=count+1; (d) ON DUPLICATE KEY UPDATE count SET count+1;

5. Using Summary Tables is a good idea when you need to optimize aggregate queries on large (>1 Million row) tables. (a) True (b) False

6. MySQL Scheduled Events can be run on regular intervals ranging from every second to every year. (a) True (b) False

7. To create a scheduled event in MySQL that executes every day at 7AM (after Nov 1, 2018), we would use the following syntax: (a) RUN DAILY STARTING '2018-11-01 07:00:00' (b) RUN DAILY START '2018-11-01' AT 7:00:00 (c) ON SCHEDULE INTERVAL 1 DAY STARTS '2018-11-01 07:00:00' (d) ON SCHEDULE EVERY 1 DAY STARTS '2018-11-01 07:00:00' (e) RUN AT STARTS '2018-11-01 07:00:00' REPEAT DAILY