Difference between revisions of "Mysql reference"

Latest revision as of 15:57, 12 April 2013

Logging into mysql via command line:

 mysql -u root -h localhost -p

Display databases:

 show databases;

Creating a new database:

 create database [DATABASE_NAME];

Delete an existing database:

 drop database [database_name];

Use existing database:

 use [database_name];

Grant priveledges and create user for a database:

 GRANT ALL ON database_name.* TO 'username'@'localhost' IDENTIFIED BY 'password';

Granting priveleges from any address

GRANT ALL ON gnucash.* TO 'username'@'%' IDENTIFIED BY 'password';

Changing the root password

 1) Login to mysql as root
 2) use main database
   mysql> use mysql;
 3) reset password for root
   mysql> UPDATE user SET password=PASSWORD('mypassword') WHERE user='root';
 4) Restart mysql server

Resetting a LOST root password

 Step # 1: Stop the MySQL server process
 Step # 2: Start the MySQL (mysqld) server/daemon process with the --skip-grant-tables option so that it will not prompt for password
 ... repeat the above steps 1-4 for "Changing the root password"

Display table data

 examples:
 SELECT * FROM database_name.tablename;
 SELECT fieldname FROM database_name.tablename;

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

 mysql> show columns from [table name];

copied from another mysql reference

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 name];

To delete a db.

 mysql> drop database [database name];

To delete a table.

 mysql> drop table [table name];

Show all data in a table.

 mysql> SELECT * FROM [table name];

Show certain selected rows with the value "whatever".

 mysql> SELECT * FROM [table name] WHERE [field name] = "whatever";

Show all records containing the name "Bob" AND the phone number '3444444'.

 mysql> SELECT * FROM [table name] 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 name] 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 name] 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 name] 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 name] WHERE rec RLIKE "^a";

Show unique records.

 mysql> SELECT DISTINCT [column name] FROM [table name];

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

 mysql> SELECT [col1],[col2] FROM [table name] ORDER BY [col2] DESC;

Return number of rows.

 mysql> SELECT COUNT(*) FROM [table name];

Sum column.

 mysql> SELECT SUM(*) FROM [table name];

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 -p
 mysql> 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 -p
 mysql> 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 root
 mysql> 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 newpassword

Allow 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 -p
 mysql> 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 -p
 mysql> 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;

 or

 mysql> grant all privileges on databasename.* to username@localhost;
 mysql> flush privileges;

To update info already in a table.

 mysql> UPDATE [table name] 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 name] where [field name] = 'whatever';

Update database permissions/privilages.

 mysql> flush privileges;

Delete a column.

 mysql> alter table [table name] drop column [column name];

Add a new column to db.

 mysql> alter table [table name] add column [new column name] varchar (20);

Change column name.

 mysql> alter table [table name] change [old column name] [new column name] varchar (50);

Make a unique column so you get no dupes.

 mysql> alter table [table name] add unique ([column name]);

Make a column bigger.

 mysql> alter table [table name] modify [column name] VARCHAR(3);

Delete unique from table.

 mysql> alter table [table name] drop index [colmn name];

Load a CSV file into a table.

 mysql> LOAD DATA INFILE '/tmp/filename.csv' replace INTO TABLE [table name] FIELDS TERMINATED BY ',' LINES TERMINATED BY '\n' (field1,field2,field3);

 mysql> CREATE TABLE [table name] (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 name] (personid int(50) not null auto_increment primary key,firstname varchar(35),middlename varchar(50),lastnamevarchar(50) default 'bato');