How do you show the currently running queries? - SHOW FULL PROCESSLIST;
How do you kill a MySQL query? - See the ID of it from the question above, then KILL id. You can separate multiple IDs by space.
I need to find out how many client connections were aborted by MySQL server. - It’s displayed in SHOW STATUS query, alternatively accessible via mysqladmin extended-status.
What does SET SQL_AUTO_IS_NULL =1 do? - you can find the last inserted row for a table that contains an AUTO_INCREMENT column by issuing WHERE auto_increment_column IS NULL
