Introduction to MySQL
MySQL is a very popular open-source relational database management system (RDBMS)
What is MySQL?
Data type | Description |
---|---|
CHAR(size) | Holds a fixed length string (can contain letters, numbers, and special characters). The fixed size is specified in parenthesis. Can store up to 255 characters |
VARCHAR(size) | Holds a variable length string (can contain letters, numbers, and special characters). The maximum size is specified in parenthesis. Can store up to 255 characters. Note: If you put a greater value than 255 it will be converted to a TEXT type |
TINYTEXT | Holds a string with a maximum length of 255 characters |
TEXT | Holds a string with a maximum length of 255 characters |
BLOB | For BLOBs (Binary Large Objects). Holds up to 65,535 bytes of data |
MEDIUMTEXT | Holds a string with a maximum length of 16,777,215 characters |
MEDIUMBLOB | For BLOBS (Binary Large Objects). Holds up to 16,777,215 bytes of data |
LONGTEXT | Holds a string with a maximum length of 4,294,967,295 characters |
LONGBLOB | For BLOBS (Binary Large Objects). Holds up to 4,294,967,295 bytes of data |
ENUM(x,y,z,etc.) | Let you enter a list of possible values. You can list up to 65535 values in an ENUM list. If a value is inserted that is not in the list, a blank value will be inserted. Note: The values are sorted in the order you enter them. You enter the possible values in this format: ENUM('X','Y', 'Z') |
SET | Similar to ENUM except that SET may contain up to 64 list items and can store more than one choice |
SELECT column1, column2, ... FROM table_name; |
SELECT column1, column2, ... FROM table_name WHERE condition; |
INSERT INTO table_name (column1, column2, column3, ...) VALUES (value1, value2, value3, ...); |
UPDATE table_name SET column1 = value1, column2 = value2, ... WHERE condition; |
DELETE FROM table_name WHERE condition; |