MySQL Multiple Choice Answer as soon as possible

1. If an EXPLAIN command shows NULL for the key column... (a) MySQL will not use any keys and will do a full table scan instead. (b) MySQL will use the default primary key index. (c) This means the key that will be used can have NULL values.

2. Which one of the following is NOT a query execution state? (a) wasting your time (b) Sorting results (c) closing tables (d) Creating tmp table (e) logging slow query (f) Sending data

3. To use the explain command we can simply add the EXPLAIN keyword to the start of a SELECT query. (a) True (b) False

4. A primary key search is the fastest index scan operation. (a) True (b) False

5. The EXPLAIN command provides info about how MySQL will optimize a query and does not execute any part of the query. (a) True (b) False

6. When using the EXPLAIN command on a query that could invoke a stored function or trigger, the EXPLAIN command summarizes the execution information of the function(s) and trigger(s) and includes it in the results. (a) True (b) False

7. You can use the EXPLAIN command to evaluate the execution of stored procedures. (a) True (b) False