MySQL Cheatsheet

Selecting a database:  mysql> USE database;  

Listing databases:  mysql> SHOW DATABASES;  

Listing tables in a db:  mysql> SHOW TABLES;  

Describing the format of a table:  mysql> DESCRIBE table;  

Creating a database:  mysql> CREATE DATABASE db_name;  

Creating a table:  mysql> CREATE TABLE table_name (field1_name TYPE(SIZE), field2_name TYPE(SIZE)); 

               Ex: mysql> CREATE TABLE pet (name VARCHAR(20), sex CHAR(1), birth DATE);  

Load tab-delimited data into a table:  mysql> LOAD DATA LOCAL INFILE "infile.txt" INTO TABLE table_name; (Use \n for NULL)  

Inserting one row at a time:  mysql> INSERT INTO table_name VALUES ('MyName', 'MyOwner', '2002-08-31'); (Use NULL for NULL)  

Retrieving information (general):  mysql> SELECT from_columns FROM table WHERE conditions; All values: SELECT * FROM table; Some values: SELECT * FROM table WHERE rec_name = "value"; Multiple critera: SELECT * FROM TABLE WHERE rec1 = "value1" AND rec2 = "value2";  

Reloading a new data set into existing table:  mysql> SET AUTOCOMMIT=1; # used for quick recreation of table mysql> DELETE FROM pet; mysql> LOAD DATA LOCAL INFILE "infile.txt" INTO TABLE table;  

Fixing all records with a certain value:  mysql> UPDATE table SET column_name = "new_value" WHERE record_name = "value";  

Selecting specific columns:  mysql> SELECT column_name FROM table; 

Retrieving unique output records:  mysql> SELECT DISTINCT column_name FROM table;  

Sorting:  mysql> SELECT col1, col2 FROM table ORDER BY col2; Backwards: SELECT col1, col2 FROM table ORDER BY col2 DESC;  

Date calculations:  mysql> SELECT CURRENT_DATE, (YEAR(CURRENT_DATE)-YEAR(date_col)) AS time_diff [FROM table]; MONTH(some_date) extracts the month value and DAYOFMONTH() extracts day.  

Pattern Matching:  mysql> SELECT * FROM table WHERE rec LIKE "blah%"; (% is wildcard - arbitrary # of chars) Find 5-char values: SELECT * FROM table WHERE rec like "_____"; (_ is any single character)  

Extended Regular Expression Matching:  mysql> SELECT * FROM table WHERE rec RLIKE "^b$"; (. for char, [...] for char class, * for 0 or more instances ^ for beginning, {n} for repeat n times, and $ for end) (RLIKE or REGEXP) To force case-sensitivity, use "REGEXP BINARY"  

Counting Rows:  mysql> SELECT COUNT(*) FROM table;  

Grouping with Counting:  mysql> SELECT owner, COUNT(*) FROM table GROUP BY owner; (GROUP BY groups together all records for each 'owner')  

Selecting from multiple tables:  (Example) mysql> SELECT pet.name, comment FROM pet, event WHERE pet.name = event.name; (You can join a table to itself to compare by using 'AS')  

Currently selected database:  mysql> SELECT DATABASE();  

Maximum value:  mysql> SELECT MAX(col_name) AS label FROM table;  

Auto-incrementing rows:  mysql> CREATE TABLE table (number INT NOT NULL AUTO_INCREMENT, name CHAR(10) NOT NULL); mysql> INSERT INTO table (name) VALUES ("tom"),("dick"),("harry");  

Adding a column to an already-created table:  mysql> ALTER TABLE tbl ADD COLUMN [column_create syntax] AFTER col_name;  

Removing a column:  mysql> ALTER TABLE tbl DROP COLUMN col; (Full ALTER TABLE syntax available at mysql.com.)  

Batch mode (feeding in a script):  # mysql -u user -p <> source batch_file;  

Backing up a database with mysqldump:  # mysqldump --opt -u username -p database > database_backup.sql (Use 'mysqldump --opt --all-databases > all_backup.sql' to backup everything.) 

(More info at MySQL's docs.)