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Thursday, July 30, 2009

MySQL Crib Sheet Cheat Sheet

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.
create database [databasename];

List all databases on the sql server.
show databases;

Switch to a database.
use [db name];

To see all the tables in the db.
show tables;

To see database's field formats.
describe [table name];

To delete a db.
drop database [database name];

To delete a table.
drop table [table name];

Show all data in a table.
SELECT * FROM [table name];

Returns the columns and column information pertaining to the designated table.
show columns from [table name];

Show certain selected rows with the value "whatever".
SELECT * FROM [table name] WHERE [field name] = "whatever";

Show all records containing the name "Bob" AND the phone number '3444444'.
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.
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'.
SELECT * FROM [table name] WHERE name like "Bob%" AND phone_number = '3444444';

Use a regular expression to find records. Use "REGEXP BINARY" to force case-sensitivity. This finds any record beginning with a.
SELECT * FROM [table name] WHERE rec RLIKE "^a$";

Show unique records.
SELECT DISTINCT [column name] FROM [table name];

Show selected records sorted in an ascending (asc) or descending (desc).
SELECT [col1],[col2] FROM [table name] ORDER BY [col2] DESC;

Return number of rows.
SELECT COUNT(*) FROM [table name];

Sum column.
SELECT SUM(*) FROM [table name];

Join tables on common columns.
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;

Switch to the mysql db. Create a new user.
INSERT INTO [table name] (Host,User,Password) VALUES('%','user',PASSWORD('password'));

Change a users password.(from unix shell).
[mysql dir]/bin/mysqladmin -u root -h hostname.blah.org -p password 'new-password';

Change a users password.(from MySQL prompt).
SET PASSWORD FOR 'user'@'hostname' = PASSWORD('passwordhere');

Allow the user "bob" to connect to the server from localhost using the password "passwd"
grant usage on *.* to bob@localhost identified by 'passwd';

Give user privilages for a db.
grant all privileges on databasename.* to username@localhost;

To update info already in a table.
UPDATE [table name] SET Select_priv = 'Y',Insert_priv = 'Y',Update_priv = 'Y' where [field name] = 'user';

Delete a row(s) from a table.
DELETE from [table name] where [field name] = 'whatever';

Update database permissions/privilages.
FLUSH PRIVILEGES;

Delete a column.
alter table [table name] drop column [column name];

Add a new column to db.
alter table [table name] add column [new column name] varchar (20);

Change column name.
alter table [table name] change [old column name] [new column name] varchar (50);

Make a unique column so you get no dupes.
alter table [table name] add unique ([column name]);

Make a column bigger.
alter table [table name] modify [column name] VARCHAR(3);

Delete unique from table.
alter table [table name] drop index [colmn name];

Load a CSV file into a table.
LOAD DATA INFILE '/tmp/filename.csv' replace INTO TABLE [table name] 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.
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.
create table [table name] (personid int(50) not null auto_increment primary key,firstname varchar(35),middlename varchar(50),lastname varchar(50) default 'bato');

Here’s a list of the commands to control mysql:
service mysqld restart
service mysqld status
service mysqld stop
service mysqld start

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