MySQL中各种字段的取值范围_MySQL
TINYINT
-128 - 127
TINYINT UNSIGNED
0 - 255
SMALLINT
-32768 - 32767
SMALLINT UNSIGNED
0 - 65535
MEDIUMINT
-8388608 - 8388607
MEDIUMINT UNSIGNED
0 - 16777215
INT 或 INTEGER
-2147483648 - 2147483647
INT UNSIGNED 或 INTEGER UNSIGNED
0 - 4294967295
BIGINT
-9223372036854775808 - 9223372036854775807
BIGINT UNSIGNED
0 - 18446744073709551615
FLOAT
-3.402823466E+38 - -1.175494351E-38
0
1.175494351E-38 - 3.402823466E+38
DOUBLE 或 DOUBLE PRECISION 或 REAL
-1.7976931348623157E+308 - -2.2250738585072014E-308
0
2.2250738585072014E-308 - 1.7976931348623157E+308
DECIMAL[(M,[D])] 或 NUMERIC(M,D)
由M(整个数字的长度,包括小数点,小数点左边的位数,小数点右边的位数,但不包括负号)和
D(小数点右边的位数)来决定,M缺省为10,D缺省为0
DATE
1000-01-01 - 9999-12-31
DATETIME
1000-01-01 00:00:00 - 9999-12-31 23:59:59
TIMESTAMP
1970-01-01 00:00:00 - 2037年的某天(具体是哪天我也不知道,呵呵)
TIME
-838:59:59' to 838:59:59
YEAR[(2|4)]
缺省为4位格式,4位格式取值范围为1901 - 2155,0000,2位格式取值范围为70-69(1970-2069)
CHAR(M) [BINARY] 或 NCHAR(M) [BINARY]
M的范围为1 - 255,如果没有BINARY项,则不分大小写,NCHAR表示使用缺省的字符集.在数据库
中以空格补足,但在取出来时末尾的空格将自动去掉.
[NATIONAL] VARCHAR(M) [BINARY]
M的范围为1 - 255.在数据库中末尾的空格将自动去掉.
TINYBLOB 或 TINYTEXT
255(2^8-1)个字符
BLOB 或 TEXT
65535(2^16-1)个字符
MEDIUMBLOB 或 MEDIUMTEXT
16777215 (2^24-1)个字符
LONGBLOB 或 LONGTEXT
4294967295 (2^32-1)个字符
ENUM('value1','value2',...)
可以总共有65535个不同的值
SET('value1','value2',...)
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