因爲以前網站使用第三方登陸,QQ暱稱比較特殊,因此用二進制的字段類型存儲。html
mysql二進制類型有:mysql
BINARYsql
VARBINARYapp
TINYBLOB, BLOB, MEDIUMBLOB, and LONGBLOB網站
順便列一下各類數據類型的存儲範圍:ui
Data Type | Storage Required |
---|---|
TINYINT |
1 byte |
SMALLINT |
2 bytes |
MEDIUMINT |
3 bytes |
INT , INTEGER |
4 bytes |
BIGINT |
8 bytes |
FLOAT( |
4 bytes if 0 <= p <= 24, 8 bytes if 25 <= p <= 53 |
FLOAT |
4 bytes |
DOUBLE [PRECISION] , REAL |
8 bytes |
DECIMAL( , NUMERIC( |
Varies; see following discussion |
BIT( |
approximately (M +7)/8 bytes |
Data Type | Storage Required Before MySQL 5.6.4 | Storage Required as of MySQL 5.6.4 |
---|---|---|
YEAR |
1 byte | 1 byte |
DATE |
3 bytes | 3 bytes |
TIME |
3 bytes | 3 bytes + fractional seconds storage |
DATETIME |
8 bytes | 5 bytes + fractional seconds storage |
TIMESTAMP |
4 bytes | 4 bytes + fractional seconds storage |
Data Type | Storage Required |
---|---|
CHAR( |
M × w bytes, 0 <= 255, where w is the number of bytes required for the maximum-length character in the character set. SeeSection 15.2.6.7, 「Physical Row Structure」 for information about CHAR data type storage requirements for InnoDB tables. |
BINARY( |
M bytes, 0 <= 255 |
VARCHAR( , VARBINARY( |
L + 1 bytes if column values require 0 − 255 bytes, L + 2 bytes if values may require more than 255 bytes |
TINYBLOB , TINYTEXT |
L + 1 bytes, 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(' |
1 or 2 bytes, depending on the number of enumeration values (65,535 values maximum) |
SET(' |
1, 2, 3, 4, or 8 bytes, depending on the number of set members (64 members maximum) |