MySQL in a Nutshell

Accurate Numeric Types

Table A-1 lists accurate numeric types. A few of these types have synonyms for compatibility. A synonym for INTEGER is INT. Synonyms for TINYINT are BIT, BOOL, and BOOLEAN. The datatypes DEC, NUMERIC, and FIXED are synonyms for DECIMAL. If UNSIGNED is used with DECIMAL, negative values are not allowed. The DECIMAL datatype is similar to floating-point numbers, but it's a fixed-point number. MySQL stores numbers in DECIMAL columns as strings. Therefore, although a numeric range appears in Table A-1, a larger number may be stored in a DECIMAL column. It may be retrieved and displayed as a string, but in a numeric context (i.e., as part of a calculation), it cannot exceed the values shown in the table.

Table A-1. Accurate numeric types

TINYINT[( width )] [UNSIGNED] [ZEROFILL]
0 bytes	Unsigned: 0 to 255
	Signed: -128 to 127
SMALLINT[( width )] [UNSIGNED] [ZEROFILL]
2 bytes	Unsigned: 0 to 65535
	Signed: -32768 to 32767
MEDIUMINT[( width )] [UNSIGNED] [ZEROFILL]	3 bytes
Unsigned: 0 to 16777215
Signed: -8388608 to 8388607	INTEGER[(width)] [UNSIGNED][ZEROFILL]
4 bytes
Unsigned: 0 to 4294967295
Signed: -2147483648 to 2147483647	BIGINT[(width)] [UNSIGNED][ZEROFILL]
8 bytes
Unsigned: 0 to 18446744073709551615
Signed: -9223372036854775808 to 9223372036854775807	DECIMAL[(width[,digits])] [UNSIGNED][ZEROFILL]
-3.402823466E+38 to -1.175494351E-38
0
1.175494351E-38 to 3.402823466E+38