The document demonstrates different SQL commands - LIKE is used to search for records where the first name starts with 'a', EXISTS checks if records exist in another table, GROUP BY groups records and counts them by a column, HAVING filters groups, and functions like ROUND and MAX are used.

1. LIKE COMMAND
mysql> Select emp_first
-> from employee
-> w here emp_first like 'a%';
+-----------+
| emp_first |
+-----------+
| Alexis |
| Ava |
+-----------+
2 row s in set (0.00 sec)
EXISTS COMMAND
mysql> select emp_id from employee
mysql> select emp_id from employee
-> w here exists (select emp_id from part_time
-> w here employee.emp_id=part_time.emp_id);
+--------+
| emp_id |
+--------+
| 1 |
| 3 |
| 5 |
| 7 |
| 9 |
+--------+
5 row s in set (0.00 sec)
GROUP BY COMMAND
mysql> select count(emp_id), emp_type from employee group by emp_type;
+---------------+----------+
| count(emp_id) | emp_type |
+---------------+----------+
| 5 | f |
| 5 | p |
+---------------+----------+
2 row s in set (0.01 sec)
HAVING COMMAND
mysql> select count(emp_id), asn_evaluation from assignment group by asn_evaluation having count(emp_id) > 5;
+---------------+----------------+
| count(emp_id) | asn_evaluation |
+---------------+----------------+
| 7 | p |
+---------------+----------------+
1 row in set (0.00 sec)

2. TWO FUNCTIONS
mysql> Select round (max(hourlyrate),1) from part_time;
+---------------------------+
| round (max(hourlyrate),1) |
+---------------------------+
| 50.7 |
+---------------------------+
1 row in set (0.00 sec)