====== SQL Cheat Sheet ======

| **Description**                                                                                                                      | **Command**                                                                                                                                                                                                                                                                                      |
| 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';                                                                                                                                                                                                              |
| 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;                                                                                                                                                                                                                                 |
| Count rows.                                                                                                                      | SELECT COUNT(*) 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');                                                                                                                                                                                                                               |
| Switch to mysql db.Give user privilages for a db.                                                                                | INSERT INTO [table name] (Host,Db,User,Select_priv,Insert_priv,Update_priv,Delete_priv,Create_priv,Drop_priv) VALUES ('%','db','user','Y','Y','Y','Y','Y','N');                                                                                                                              |
| 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');                                                                                                                           |