[MySQL] Data Type & bytes

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Storage Requirements for Numeric Types

Data Type	Storage Required
TINYINT	1 byte
SMALLINT	2 bytes
MEDIUMINT	3 bytes
INT, INTEGER	4 bytes
BIGINT	8 bytes
FLOAT(p)	4 bytes if 0 <= p <= 24, 8 bytes if 25 <= p <= 53
FLOAT	4 bytes
DOUBLE [PRECISION], REAL	8 bytes
DECIMAL(M,D), NUMERIC(M,D)	Varies; see following discussion
BIT(M)	approximately (M+7)/8 bytes

Storage Requirements for Date and Time Types

Data Type	Storage Required
DATE	3 bytes
DATETIME	8 bytes
TIMESTAMP	4 bytes
TIME	3 bytes
YEAR	1 byte

 

Storage Requirements for String Types

Data Type	Storage Required
CHAR(M)	M bytes, 0 <= M <= 255
VARCHAR(M)	L + 1 bytes, where L <= M and 0 <= M <= 255 (see note below) or L + 2 bytes, where L <= M and 256 <= M <= 65535 (see note below).
BINARY(M)	M bytes, 0 <= M <= 255
VARBINARY(M)	L + 1 bytes, where L <= M and 0 <= M <= 255 (see note below) or L + 2 bytes, where L <= M and 256 <= M <= 65535 (see note below).
TINYBLOB, TINYTEXT	L+1 byte, where L < 28
BLOB, TEXT	L+2 bytes, where L < 216
MEDIUMBLOB, MEDIUMTEXT	L+3 bytes, where L < 224
LONGBLOB, LONGTEXT	L+4 bytes, where L < 232
ENUM('value1','value2',...)	1 or 2 bytes, depending on the number of enumeration values (65,535 values maximum)
SET('value1','value2',...)	1, 2, 3, 4, or 8 bytes, depending on the number of set members (64 members maximum)