MySQL byte problem, Chinese and digital

Test under MySQL 5.1.5-alpha to the conclusion

Latin1:

1character=1byte, 1 kanji =2character,

In other words, a field is defined as varchar (200), it can store 100 characters or 200 letters.

This should be noted, especially when the field content is composed of letters and Chinese characters, as far as possible to assume that the field content is composed of Chinese characters, set the field length accordingly

UTF8:

1character=3bytes, 1 Kanji =1character

In other words, a field is defined as varchar (200), it can store 200 characters or 200 letters.

Gbk

1character=2bytes,1 Kanji =1character

In other words, a field is defined as varchar (200), it can store 200 characters or 200 letters.

The number type calculates the range represented by the number of bytes  tinyint                         &NBSP ;          1 byte  smallint                                 2 bytes  mediumint                 &N Bsp            3 bytes  int                   &NB Sp                       4 bytes  integer       &NBSP ;                           4 bytes  bigint                                     &NBSP;8 Bytes  float (X)                                 &NBSp;4 if X < = 24 or 8 If < = X < = 53 float                                       4 bytes  double                                    8 bytes  double PRECISION &nb Sp                8 bytes  real               &N Bsp                         8 bytes  decimal (m,d)                          m byte (d+2, if M < D)  numeric (m,d)                          m byte (d+2, if M < D)    date and time Type Date                                 &NB Sp   &NBSP  3 bytes  datetime                           &NBSP ;     8 bytes  timestamp                         &NB Sp     4 bytes  time                           & nbsp             3 bytes  year                   & nbsp                     1 byte    string type char (M)       &N Bsp                                m byte, 1 <= M <= 255 varchar (m)                           &N Bsp     l+1 bytes, in this L <= m and 1 <= m <= 255 tinyblob, Tinytext           &NBsp         l+1 byte, in this l< 2 ^ 8 blob, TEXT                                   l+2 byte, in this l< 2 ^ 16 mediumblob, Mediumtext   & nbsp     L+3 Byte, in this l< 2 ^ 24 longblob, longtext                 L+4 word section, in this l< 2 ^ 32 enum (' value1 ', ' value2 ',...)                1 or 2 bytes, depending on the enumeration Number of values (maximum value 65535)  set (' value1 ', ' value2 ',...)                    1,2, 3,4 or 8 bytes, depending on the number of members of the collection (up to 64 members)   where: 1. bit: bit
One binary data 0 or 1, is 1bit;
2. Byte: Byte
The basic unit of measurement for storage space, such as: the definition of VARCHAR (45) in MySQL means 45 bytes;
1 byte = 8 bit
3. A single byte of an English character;
1 letter = 1 byte = 8 bit
4. A kanji account of 2 bytes;
1 Kanji = 2 byte = + bit
BYTE: one byte (8 bits) ( -128~127) (-2 of 7 to 2 of 7) (1)
Short: two bytes (16 bits) ( -32768~32767) (-2 15 to 2 15)
Int: four bytes (32 bits) (one word length) ( -2147483648~2147483647) (-2 31 to 2 31)
Long: Eight bytes (64 bits) ( -9223372036854774808~9223372036854774807) (-2 of 63 parties to 2 63)-1
Float: four bytes (32 bits) (3.402823e+38 ~ 1.401298e-45) (e+38 is multiplied by 10 38, e-45 is multiplied by 10 minus 45 times)
Double: eight bytes (64 bits) (1.797693e+308~ 4.9000000e-324

MySQL byte problem, Chinese and digital