FLUSH PRIVILEGES;


An alternative (and apparently official one) is by using the syntax below.

SET PASSWORD [FOR user] =
{
PASSWORD('some password')
| OLD_PASSWORD('some password')
| 'encrypted password'
}

Example :

SET PASSWORD 'kwatog'@'localhost = PASSWORD('mynewpassword')


Still can’t believe? Go head to the official documentation of MySQL at the following URL.

http://dev.mysql.com/doc/refman/5.0/en/set-password.html

Here’s the log of mysql (/var/log/mysqld.log)

110514 14:04:22 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
110514 14:04:22 [Note] Plugin 'InnoDB' is disabled.
110514 14:04:22 [Note] Plugin 'FEDERATED' is disabled.
/usr/libexec/mysqld: Table 'mysql.plugin' doesn't exist
110514 14:04:22 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it.
110514 14:04:22 [ERROR] Unknown/unsupported storage engine: InnoDB
110514 14:04:22 [ERROR] Aborting


Initially, I thought the problem was on the mysql_upgrade part because that’s the first error that appears on the log. Apparently, that’s just a warning message because the service still managed to proceed to the next step which is for the InnoDB. And based on the log, it failed to start and actually aborted. So that’s where I should concentrate my investigation/trial-and-error.

Solution

I opened /etc/my.cnf and comment out skip-innodb and then restart mysqld. It fixed the problem and mysql managed to start. I then proceeded with the mysql_upgrade which is unrelated to the error.

Another solution for this is to set the default storage to other than InnoDB. However, I haven’t tried that myself.

Reload MySQL Backup to DB
In case you want to reload your backup, here’s the syntax for it.

mysql -u<dbuserid> -p <dbase_name> < <path/filename>


Sample

mysql -uroot -p wp_dbase < /usr/kwatog/wpdb_20100813.sql


Again, it’s so easy, no?

DATE ADD (SYSDATE +/-1)

SELECT DATE_ADD(SYSDATE(),INTERVAL 1 DAY);
SELECT DATE_ADD(SYSDATE(),INTERVAL -10 DAY);


ADD_MONTHS

SELECT DATE_ADD(SYSDATE(),INTERVAL 1 MONTH);


TRUNC()

SELECT DATE(SYSDATE());


TO_DATE()

SELECT STR_TO_DATE( '07-08-2010', '%d-%m-%Y' );

TIME DIFFERENCE

SELECT TIMESTAMPDIFF(
SECOND , '2010-01-07 23:50:59', SYSDATE( ) ) /3600 /24 day,
TIMESTAMPDIFF(
SECOND , '2010-01-07 23:50:59', SYSDATE( ) ) /3600 hours,
TIMESTAMPDIFF(
SECOND , '2010-01-07 23:50:59', SYSDATE( ) ) /60 mins,
TIMESTAMPDIFF(
SECOND , '2010-01-07 23:50:59', SYSDATE( ) ) secs,

In the preceding example, I could have just used HOUR, MINUTE, DAY, MONTH or YEAR interval but in real world, I mostly use SECOND for a more accurate results. That’s not to say timestampdiff is not accurate. Maybe because I’m used in how I do it in Oracle.

MONTHS_BETWEEN

SELECT TIMESTAMPDIFF(
MONTH , '2010-01-07', SYSDATE( ) ) no_months


Reference:

http://dev.mysql.com/doc/refman/5.1/en/date-and-time-functions.html

You can recover MySQL database server password with following five easy steps.

Step # 1: Stop the MySQL server process.

# /etc/init.d/mysqld stop

Step # 2: Start the MySQL (mysqld) server/daemon process with the –skip-grant-tables option so that it will not prompt for password.

# mysqld_safe --skip-grant-tables &

Step # 3: Connect to mysql server as the root user.
# mysql -u root
Step # 4: Setup new mysql root account password.

mysql> use mysql;
mysql> update user set password=PASSWORD("NEW-ROOT-PASSWORD") where User='root';
mysql> flush privileges;
mysql> quit


Step # 5: Exit and restart the MySQL server.
# /etc/init.d/mysqld stop

Step # 6: Start MySQL server and test it
# /etc/init.d/mysqld start
# mysql -u root -p

The steps are basically the same when resetting the password in other linux flavors. I’m using the same steps in Ubuntu but with a slight difference in shell commands.

reference :
http://dev.mysql.com/doc/refman/5.0/en/resetting-permissions.html

Syntax


IFNULL(expr1,expr2)


Usage

If expr1 is not NULL, IFNULL() returns expr1; otherwise it returns expr2. Take note that IFNULL() returns a numeric or string value, depending on the context in which it is used. I haven’t used it for other data types yet but I reckon it would have the same results. That is to return the same data type as that of expr1. Another important thing to remember is that expr1 and expr2 should have the same data type

Case in point is the alpha-numeric auto-generated code. In Oracle, it’s easy to generate AA123, AA124, AA125, etc., etc. All we have to do is concat the alpha part (AA) and with the nextval of sequence. For MySQL, the alpha part and the numeric part have to be saved in separate fields.

However, Maresa of Microshell has created an alternative solution for it. The article discusses a way to emulate the nextval function in mysql. It a nutshell, they created a table similar to the all_sequences of Oracle. This is where you insert your sequences. Then, create a function named nextval() function which increments and returns value of the sequence.
You can check the procedure here.

It’s pretty neat, actually. It’s an excellent alternative and you can even create similar functions like currval(), prevval(), among others. However, I have some reservations on his approach especially on the issue of concurrency. You see in Oracle, calling the nextval() will increment the value and that’s already persisted (saved) in the sequence table even without saving your query/dml statement. On this approach, other queries accessing the pseudo-nextval will have to wait until your query finishes. Not a good idea.

So for now, I’ll will still have to make do with whatever MySQL is providing. If there’s any consolation, MySQL provides LAST_INSERT_ID() function in case you want to get the latest id inserted. See details here here.

So I’m just hoping that MySQL will implement an equivalent feature in the near future. With the imminent takeover by Oracle, I’m actually hoping that development of MySQL will push through and take a steam. We all know that the development of this widely used open-source database engine has been hampered ever since Sun bought it.

Sequence is a little feature. But little as it seems, it solves a lot of problems and helps improve code development time.


-bash-3.2$mysqldump -ujhondoe -p mydb_name > mydb_name_backup.sql
password:
-bash-3.2$ zip mydb_name_backup.zip mydb_name_backup.sql


Load MySQL Backup Into Database


-bash-3.2$mysql -ujhondoe mydb_name < mydb_name_backup.sql
password:


Create User in MySQL


mysql> CREATE USER 'jhondoe'@'localhost' IDENTIFIED BY 'mypassword';
mysql> GRANT ALL PRIVILEGES ON mydbname.* TO 'jhondoe'@'localhost' WITH GRANT OPTION;

mysql> CREATE USER 'jhondoe'@'%' IDENTIFIED BY 'mypassword';
mysql> GRANT ALL PRIVILEGES ON mydbname.* TO 'monty'@'%' WITH GRANT OPTION;