- CHAR: used for columns with values of an exact length
Ex: CHAR(2) for state abbreviations like "PA" and "NY"
- VARCHAR: used for columns with values of variable lengths up to 255
Ex: VARCHAR(25) for names
- TEXT: used for free-form text such as comments of up to ~65000 characters
- MEDIUMTEXT: free-form text of up to ~1.6 million characters
- LONGTEXT: free-form text of up to ~4 trillion characters
The data types for storing integers are shown in the table below. As the table shows, columns of these types can be signed or unsigned. Unsigned columns can only hold positive values. Signed columns can hold both positive and negative values.
|Type||Signed Range||Unsigned Range|
|TINYINT||-128 to 128||0 to 255|
|SMALLINT||-32768 to 32767||0 to 65535|
|MEDIUMINT||-8.3M to 8.3M||0 to 16M|
|INT||-2.1B to 2.1B||0 to 4.2B|
|BIGINT||> ±2.1B||> 4.2B|
For numbers that have digits after the decimal point, there are two main data types:
- FLOAT: used for numbers with up to 7 significant digits
- DOUBLE: used for numbers with up to 16 significant digits
The data type limits above are approximate in many cases.