One cannot handle the vast amount of data present in the world without a proper database management system. MySQL is one of the most popular database management systems used in the industry. In my previous blog on MySQL Tutorial, you would have got an understanding of the various SQL queries that can be executed. In this blog on MySQL Data Types, I will be discussing the different data types used in MySQL.
Table of Content
In this blog on MySQL Data Types, I’m going to cover the following:
Numeric Datatypes allow both signed and unsigned integers. MySQL supports the following numeric data types.
Data Type
Description
Storage
TINYINT(size)
Allows signed integers -128 to 127 and 0 to 255 unsigned integers.
1 byte
SMALLINT(size)
Allows signed integers from -32768 to 32767 and 0 to 65535 unsigned integers.
2 bytes
MEDIUMINT(size)
Allows signed integers from -8388608 to 8388607 and 0 to 16777215 unsigned integers.
3 bytes
INT(size)
Allows signed integers from -2147483638 to 214747483637 and 0 to 4294967925 unsigned integers.
4 bytes
BIGINT(size)
Allows signed integers from -9223372036854775808 to 9223372036854775807 and 0 to 18446744073709551615 unsigned integers.
8 bytes
FLOAT(size,d)
Allows small numbers with floating decimal point. The size parameter is used to specify the maximum number of digits, and the d parameter is used to specify the maximum number of digits to the right of the decimal.
4 bytes
DOUBLE(size,d)
Allows large numbers with floating decimal point. The size parameter is used to specify the maximum number of digits, and the d parameter is used to specify the maximum number of digits to the right of the decimal.
8 bytes
DECIMAL(size,d)
Allows storing DOUBLE as a string, so that there is a fixed decimal point. The size parameter is used to specify the maximum number of digits, and the d parameter is used to specify the maximum number of digits to the right of the decimal.
Varies
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MySQL Data Types: String Types
String Data types allow both fixed and variable length strings. MySQL supports the following String data types.
Data Type
Description
Storage
CHAR(size)
Holds up to 255 characters and allows a fixed length string.
(Declared column length of characters * Number of bytes) <= 255
VARCHAR(size)
Holds up to 255 characters and allows a variable length string. If you store characters greater than 55, then the data type will be converted to TEXT type.
String value(Len) + 2 bytes WHERE column values may require more than 255 bytes
TINYTEXT
Allows a string with a maximum length of 255 characters
Actual length in bytes of String value(Len) + 1 bytes, where Len < 28
TEXT
Allows a string with a maximum length of 65,535 characters
Actual length in bytes of String value(Len) + 2 bytes, where Len < 216
BLOB
Holds up to 65,535 bytes of data, and is used for Binary Large Objects.
Actual length in bytes of String value(Len) + 2 bytes, where Len < 216
MEDIUMTEXT
Allows a string with a maximum length of 16,777,215 characters
Actual length in bytes of String value(Len) + 3 bytes, where Len < 224
MEDIUMBLOB
Holds up to 16,777,215 bytes of data, and is used for Binary Large Objects.
Actual length in bytes of String value(Len) + 3 bytes, where Len < 224
LONGTEXT
Allows a string with a maximum length of 4,294,967,295 characters
Actual length in bytes of String value(Len) + 4 bytes, where Len < 232
LONGBLOB
Holds up to 4,294,967,295 bytes of data, and is used for Binary Large Objects.
Actual length in bytes of String value(Len) + 4 bytes, where Len < 232
ENUM(x,y,z,etc.)
Allows you to enter a list of possible values, with the maximum to be 65535 values. Just in case a value is inserted which is not present in the list, a blank value will be inserted.
1 or 2 bytes, depending on the number of enumeration values (65,535 values maximum)
SET
This data type is similar to ENUM, but SET can have up to 64 list items and can store more than one choice.
1, 2, 3, 4, or 8 bytes, depending on the number of set members (64 members maximum)
This data type enables us to mention the date and time. MySQL supports the following Date & Time data types.
Data Type
Description
Storage Required Before MySQL 5.6.4
Storage Required as of MySQL 5.6.4
YEAR()
Holds the value of year either in a two digit or in a four-digit format. Year values in the range (70-99) are converted to (1970-1999), and year values in the range (00-69) are converted to (2000-2069)
1 byte
1 byte
DATE()
Holds the date values in the format: YYYY-MM-DD, where the supported range is (1000-01-01) to (9999-12-31)
3 bytes
3 bytes
TIME()
Holds the time values in the format: HH:MI:SS, where the supported range is (-838:59:59) to (838:59:59)
3 bytes
3 bytes + fractional seconds storage
DATETIME()
A combination of date and time values in the format: YYYY-MM-DD HH:MI:SS, where the supported range is from ‘1000-01-01 00:00:00’ to ‘9999-12-31 23:59:59’
8 bytes
5 bytes + fractional seconds storage
TIMESTAMP()
Holds values which are stored as the number of seconds, with the format (YYYY-MM-DD HH:MI: SS). The supported range is from (1970-01-01 00:00:01) UTC to (2038-01-09 03:14:07) UTC
4 bytes
4 bytes + fractional second storage
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MySQL Data Types: Using Data Types from Other Database Engines
If you want to implement the code written by other vendors in SQL, then, MySQL facilitates this by mapping data types. Refer to the following table.
Other Vendor Type
MySQL Type
BOOL
TINYINT
BOOLEAN
TINYINT
CHARACTER VARYING(M)
VARCHAR(M)
FIXED
DECIMAL
FLOAT4
FLOAT
FLOAT8
DOUBLE
INT1
TINYINT
INT2
SMALLINT
INT3
MEDIUMINT
INT4
INT
INT8
BIGINT
LONG VARBINARY
MEDIUMBLOB
LONG VARCHAR
MEDIUMTEXT
LONG
MEDIUMTEXT
MIDDLEINT
MEDIUMINT
NUMERIC
DECIMAL
After this blog on MySQL Data Types, we will be getting into connecting databases with PHP, but before that you can refer to this SQL Interview Questions blog, to know the top questions asked in interviews. Stay tuned!
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Got a question for us? Please mention it in the comments section of ” MySQL Data Types” and I will get back to you.
