mysql常用字段类型及size大小
Posted On 2012年8月13日
mysql 里各种字段类型的size大小及描述.
| Ty p e | S i z e | D e s c r i p t i o n |
| CHAR[Length] | Length bytes | A fixed-length field from 0 to 255 characters long. |
| VARCHAR(Length) | String length + 1 bytes | A fixed-length field from 0 to 255 characters long. |
| TINYTEXT/TINYBLOG | String length + 1 bytes | A string with a maximum length of 255 characters. |
| TEXT/BLOB | String length + 2 bytes | A string with a maximum length of 65,535 characters. |
| MEDIUMTEXT/MEDIUMBLOB | String length + 3 bytes | A string with a maximum length of 16,777,215 characters. |
| LONGTEXT/LONGBLOB | String length + 4 bytes | A string with a maximum length of 4,294,967,295 characters. |
| TINYINT[Length] | 1 byte | Range of -128 to 127 or 0 to 255 unsigned. |
| SMALLINT[Length] | 2 bytes | Range of -32,768 to 32,767 or 0 to 65535 unsigned. |
| MEDIUMINT[Length] | 3 bytes | Range of -8,388,608 to 8,388,607 or 0 to 16,777,215 unsigned. |
| INT[Length] | 4 bytes | Range of -2,147,483,648 to 2,147,483,647 or 0 to 4,294,967,295 unsigned. |
| BIGINT[Length] | 8 bytes | Range of -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807 or 0 to 18,446,744,073,709,551,615 unsigned. |
| FLOAT | 4 bytes | A small number with a floating decimal point. |
| DOUBLE[Length, Decimals] | 8 bytes | A large number with a floating decimal point. |
| DECIMAL[Length, Decimals] | Length + 1 or Length + 2 bytes | A DOUBLE stored as a string, allowing for a fixed decimal point. |
| DATE | 3 bytes | In the format of YYYY-MM-DD. |
| DATETIME | 8 bytes | In the format of YYYY-MM-DD HH:MM:SS. |
| TIMESTAMP | 4 bytes | In the format of YYYYMMDDHHMMSS; acceptable range ends inthe year 2037. |
| TIME | 3 bytes | In the format of HH:MM:SS |
| ENUM | 1 or 2 bytes | Short for enumeration, which means that each column can haveone of several possible values. |
| SET | 1, 2, 3, 4, or 8 bytes | Like ENUM except that each column can have more than one ofseveral possible values. |
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