Scenario: Someone wants to know which of the over 50 MySQL users have certain privileges.

There are many ways to solve this problem. Some of these scenarios are tedious and repetitious, others take no time at all.

The issue, of course, lies in what the “certain” privileges are. If it is “who has the SUPER privilege?” then a simple

SELECT user,host FROM mysql.user WHERE Super_priv='Y';

is sufficient. If it is “who has write access to the foo database”, you might write:

SELECT user,host FROM db WHERE Db='foo' AND Select_priv='Y';

but that only shows who explicitly has read permissions on that database; it does not include those who have global read permissions. The full query would be:
(more…)

The answers to the last pop quiz are up: http://www.pythian.com/blogs/868/pop-quiz-mysql-cluster

So here’s another pop quiz. Given the following:

Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 16450949 to server version: 4.1.14-standard-log

Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

mysql> select count(*),length(password) from mysql.user group by length(password);
+----------+------------------+
| count(*) | length(password) |
+----------+------------------+
|       49 |               16 |
|       31 |               41 |
+----------+------------------+
2 rows in set (0.00 sec)

mysql> select password('foo');
+-------------------------------------------+
| password('foo')                           |
+-------------------------------------------+
| *F3A2A51A9B0F2BE2468926B4132313728C250DBF | …