handy Mysql commands

This is a list of handy MySQL commands that I use time and time again. At the bottom are statements, clauses, and functions you can use in MySQL.

Below that are PHP and Perl API functions you can use to interface with MySQL. To use those you will need to build PHP with MySQL functionality.

To use MySQL with Perl you will need to use the Perl modules DBI and DBD::mysql.

Below when you see # it means from the unix shell.

When you see mysql> it means from a MySQL prompt after logging into MySQL.

To login (from unix shell) use -h only if needed.

# [mysql dir]/bin/mysql -h hostname -u root -p

Create a database on the sql server.

mysql> create database [databasename];

List all databases on the sql server.

mysql> show databases;

Switch to a database.

mysql> use [db name];

To see all the tables in the db.

mysql> show tables;

To see database’s field formats.

mysql> describe [table “” not found /];

To delete a db.

mysql> drop database [database name];

To delete a table.

mysql> drop table [table “” not found /]

Show all data in a table.

mysql> SELECT * FROM [table “” not found /];

Returns the columns and column information pertaining to the designated table.

mysql> show columns from [table “” not found /];

mysql> SELECT * FROM [table “” not found /]

WHERE [field name] = “whatever”;

Show all records containing the name “Bob” AND the phone number ‘3444444’.

mysql> SELECT * FROM [table “” not found /]

WHERE name = “Bob” AND phone_number = ‘3444444’;

Show all records not containing the name “Bob” AND the phone number ‘3444444’ order by the phone_number field.

mysql> SELECT * FROM [table “” not found /]

WHERE name != “Bob” AND phone_number = ‘3444444’ order by phone_number;

Show all records starting with the letters ‘bob’ AND the phone number ‘3444444’.

mysql> SELECT * FROM [table “” not found /]

WHERE name like “Bob%” AND phone_number = ‘3444444’;

Show all records starting with the letters ‘bob’ AND the phone number ‘3444444’ limit to records 1 through 5.

mysql> SELECT * FROM [table “” not found /]

WHERE name like “Bob%” AND phone_number = ‘3444444’ limit 1,5;

Use a regular expression to find records. Use “REGEXP BINARY” to force case-sensitivity. This finds any record beginning with a.

mysql> SELECT * FROM [table “” not found /]

WHERE rec RLIKE “^a”;

Show unique records.

mysql> SELECT DISTINCT [column name] FROM [table “” not found /];

Show selected records sorted in an ascending (asc) or descending (desc).

mysql> SELECT [col1],[col2] FROM [table “” not found /]

ORDER BY [col2] DESC;

Return number of rows.

mysql> SELECT COUNT(*) FROM [table “” not found /];

Sum column.

mysql> SELECT SUM(*) FROM [table “” not found /];

Join tables on common columns.

mysql> select lookup.illustrationid, lookup.personid,person.birthday from lookup left join person on lookup.personid=person.personid=statement to join birthday in person table with primary illustration id;

Creating a new user. Login as root. Switch to the MySQL db. Make the user. Update privs.

# mysql -u root -pmysql> use mysql;mysql> INSERT INTO user (Host,User,Password) VALUES(‘%’,’username’,PASSWORD(‘password’));mysql> flush privileges;

Change a users password from unix shell.

# [mysql dir]/bin/mysqladmin -u username -h hostname.blah.org -p password ‘new-password’

Change a users password from MySQL prompt. Login as root. Set the password. Update privs.

# mysql -u root -pmysql> SET PASSWORD FOR ‘user’@’hostname’ = PASSWORD(‘passwordhere’);mysql> flush privileges;Recover a MySQL root password.Stop the MySQL server process.Start again with no grant tables.Login to MySQL as root. Set new password.Exit MySQL and restart MySQL server.# /etc/init.d/mysql stop# mysqld_safe –skip-grant-tables &# mysql -u rootmysql> use mysql;mysql> update user set password=PASSWORD(“newrootpassword”) where User=’root’;mysql> flush privileges;mysql> quit# /etc/init.d/mysql stop# /etc/init.d/mysql start

Set a root password if there is on root password.

# mysqladmin -u root password newpassword

Update a root password.

# mysqladmin -u root -p oldpassword newpasswordAllow the user “bob” to connect to the server from localhost using the password “passwd”.Login as root.Switch to the MySQL db.Give privs.Update privs.# mysql -u root -pmysql> use mysql;mysql> grant usage on *.* to bob@localhost identified by ‘passwd’;mysql> flush privileges;Give user privilages for a db.Login as root.Switch to the MySQL db.Grant privs.Update privs.# mysql -u root -pmysql> use mysql;mysql> INSERT INTO db (Host,Db,User,Select_priv,Insert_priv,Update_priv,Delete_priv,Create_priv,Drop_priv) VALUES (‘%’,’databasename’,’username’,’Y’,’Y’,’Y’,’Y’,’Y’,’N’);mysql> flush privileges;ormysql> grant all privileges on databasename.* to username@localhost;mysql> flush privileges;

To update info already in a table.

mysql> UPDATE [table “” not found /]

SET Select_priv = ‘Y’,Insert_priv = ‘Y’,Update_priv = ‘Y’ where [field name] = ‘user’;

Delete a row(s) from a table.

mysql> DELETE from [table “” not found /]

where [field name] = ‘whatever’;

Update database permissions/privilages.

mysql> flush privileges;

Delete a column.

mysql> alter table [table “” not found /]

drop column [column name];

Add a new column to db.

mysql> alter table [table “” not found /]

add column [new column name] varchar (20);

Change column name.

mysql> alter table [table “” not found /]

change [old column name] [new column name] varchar (50);

Make a unique column so you get no dupes.

mysql> alter table [table “” not found /]

add unique ([column name]);

Make a column bigger.

mysql> alter table [table “” not found /]

modify [column name] VARCHAR(3);

Delete unique from table.

mysql> alter table [table “” not found /]

drop index [colmn name];

Load a CSV file into a table.

mysql> LOAD DATA INFILE ‘/tmp/filename.csv’ replace INTO TABLE [table “” not found /]

FIELDS TERMINATED BY ‘,’ LINES TERMINATED BY ‘\n’ (field1,field2,field3);

Dump all databases for backup. Backup file is sql commands to recreate all db’s.

# [mysql dir]/bin/mysqldump -u root -ppassword –opt >/tmp/alldatabases.sql

Dump one database for backup.

# [mysql dir]/bin/mysqldump -u username -ppassword –databases databasename >/tmp/databasename.sql

Dump a table from a database.

# [mysql dir]/bin/mysqldump -c -u username -ppassword databasename tablename > /tmp/databasename.tablename.sql

Restore database (or database table) from backup.

# [mysql dir]/bin/mysql -u username -ppassword databasename < /tmp/databasename.sql

Create Table Example 1.

mysql> CREATE TABLE [table “” not found /]

(firstname VARCHAR(20), middleinitial VARCHAR(3), lastname VARCHAR(35),suffix VARCHAR(3),officeid VARCHAR(10),userid VARCHAR(15),username VARCHAR(8),email VARCHAR(35),phone VARCHAR(25), groups VARCHAR(15),datestamp DATE,timestamp time,pgpemail VARCHAR(255));

Create Table Example 2.

mysql> create table [table “” not found /]

(personid int(50) not null auto_increment primary key,firstname varchar(35);

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