MySQL - Data Types

A Data Type is an attribute which specifies the type of data that will be stored inside each column when creating a table. The data type is a guideline for MySQL to understand what type of data is expected inside of each column, and it also identifies how MySQL will interact with the stored data.

In MySQL, the data types can be mainly classified into three categories:

String Data Types
Numeric Data Types
Date and time Data Types

String Data Types

Data type	Description
CHAR(size)	A FIXED length string that can contain letters, numbers, and special characters. The size parameter specifies the column length in characters. It can be from 0 to 255. Default is 1.
VARCHAR(size)	A VARIABLE length string that can contain letters, numbers, and special characters. The size parameter specifies the maximum column length in characters. It can be from 0 to 65535.
BINARY(size)	Equal to CHAR(), but stores binary byte strings. The size parameter specifies the column length in bytes. Default is 1.
VARBINARY(size)	Equal to VARCHAR(), but stores binary byte strings. The size parameter specifies the maximum column length in bytes.
TINYTEXT(size)	Holds a string with a maximum length of 255 characters.
TEXT(size)	Holds a string with a maximum length of 65,535 bytes.
MEDIUMTEXT(size)	Holds a string with a maximum length of 16,777,215 characters.
LONGTEXT(size)	Holds a string with a maximum length of 4,294,967,295 characters.
ENUM(val1, val2, val3, ...)	A string object that can have only one value, chosen from a list of possible values. It is possible to 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. The values are sorted in the order it is entered.
SET(val1, val2, val3, ...)	A string object that can have 0 or more values, chosen from a list of possible values. It is possible to list up to 64 values in a SET list.
TINYBLOB	Used for BLOBs (Binary Large Objects). Max length: 255 bytes.
BLOB(size)	Used for BLOBs (Binary Large Objects). Holds up to 65,535 bytes of data.
MEDIUMBLOB	Used for BLOBs (Binary Large Objects). Holds up to 16,777,215 bytes of data.
LONGBLOB	Used for BLOBs (Binary Large Objects). Holds up to 4,294,967,295 bytes of data.

Numeric Data Types

Data type	Description
BOOL	Zero is considered as false, nonzero values are considered as true.
BOOLEAN	Equal to BOOL
BIT(size)	A bit-value type. The number of bits per value is specified in size. The size parameter can hold a value from 1 to 64. Default is 1.
TINYINT(size)	A very small integer. Signed range is from -128 to 127. Unsigned range is from 0 to 255. The size parameter specifies the maximum display width (which is 255)
SMALLINT(size)	A small integer. Signed range is from -32768 to 32767. Unsigned range is from 0 to 65535. The size parameter specifies the maximum display width (which is 255)
MEDIUMINT(size)	A medium integer. Signed range is from -8388608 to 8388607. Unsigned range is from 0 to 16777215. The size parameter specifies the maximum display width (which is 255)
INT(size)	An integer value. Signed range is from -2147483648 to 2147483647. Unsigned range is from 0 to 4294967295. The size parameter specifies the maximum display width (which is 255)
INTEGER(size)	Equal to INT(size)
BIGINT(size)	A large integer. Signed range is from -9223372036854775808 to 9223372036854775807. Unsigned range is from 0 to 18446744073709551615. The size parameter specifies the maximum display width (which is 255)
FLOAT(size, d)	A floating point number. The total number of digits is specified in size. The number of digits after the decimal point is specified in the d parameter. It is deprecated in MySQL 8.0.17, and it will be removed in future versions.
FLOAT(p)	A floating point number. MySQL uses the p value to determine whether to use FLOAT or DOUBLE for the resulting data type. If p is from 0 to 24, the data type becomes FLOAT(). If p is from 25 to 53, the data type becomes DOUBLE().
DOUBLE(size, d)	A normal-size floating point number. The total number of digits is specified in size. The number of digits after the decimal point is specified in the d parameter
DOUBLE PRECISION(size, d)	Synonyms for DOUBLE.
REAL(size, d)	Synonyms for DOUBLE.
DECIMAL(size, d)	An exact fixed-point number. The total number of digits is specified in size. The number of digits after the decimal point is specified in the d parameter. The maximum number for size is 65. The maximum number for d is 30. The default value for size is 10. The default value for d is 0.
DEC(size, d)	Equal to DECIMAL(size, d)
NUMERIC(size, d)	Equal to DECIMAL(size, d)
FIXED(size, d)	Equal to DECIMAL(size, d)

Note: All the numeric data types may have an extra option: UNSIGNED or ZEROFILL. If UNSIGNED option is added, MySQL disallows negative values for the column. If ZEROFILL option is added, MySQL automatically also adds the UNSIGNED attribute to the column.

Date and Time Data Types

Data type	Description
DATE	A date. Format: YYYY-MM-DD. The supported range is from '1000-01-01' to '9999-12-31'.
DATETIME(fsp)	A date and time combination. Format: YYYY-MM-DD hh:mm:ss. The supported range is from '1000-01-01 00:00:00' to '9999-12-31 23:59:59'. Adding DEFAULT and ON UPDATE in the column definition to get automatic initialization and updating to the current date and time.
TIMESTAMP(fsp)	A timestamp. TIMESTAMP values are stored as the number of seconds since the Unix epoch ('1970-01-01 00:00:00' UTC). Format: YYYY-MM-DD hh:mm:ss. The supported range is from '1970-01-01 00:00:01' UTC to '2038-01-09 03:14:07' UTC. Automatic initialization and updating to the current date and time can be specified using DEFAULT CURRENT_TIMESTAMP and ON UPDATE CURRENT_TIMESTAMP in the column definition.
TIME(fsp)	A time. Format: hh:mm:ss. The supported range is from '-838:59:59' to '838:59:59'.
YEAR	A year in four-digit format. Values allowed in four-digit format: 1901 to 2155, and 0000. Since MySQL 8.0, it does not support year in two-digit format.