MySQL数据库的数据类型

1.整型:

    整数类型                    字节                    最小值                                            最大值

    TINYINT                    1                有符号-128,无符号0               有符号127,无符号255

    SMALLINT                2                 有符号-32768,无符号0            有符号32767,无符号65535

    MEDIUMINT            3                 有符号-8388608,无符号0        有符号8388607,无符号1677215

    INT和INTEGER         4                 有符号-2147483648,无符号0   有符号2147483647,无符号4294967295

    BIGINT                     8                 有符号-9223372036854775808,无符号0        

                                                                                         有符号9223372036854775807,无符号18446744073709551615

2.通过DOS查看相关类型:

    

    

3.浮点数类型,定点数类型和位类型:

    浮点数类型            字节                最小值                                            最大值

        FLOAT                 4                 + -1.75494351E-38             + -3.402823466E + 38

        DOUBLE              8                 + -2.2250738585072014E-308 + -1.7976931348623517E + 308

    定点数类型            字节                最小值                                            最大值

    DEC(M,D)和DECIMAL(M,D)M + 2与DOUBLE相同和DOUBLE相同

    DEC和DECIMAL这两个定点数类型是同名词,有效取值有中号和d决定,精度比DOUBLE还高,DECIMAL存储的是字符串,提供更高的精度

    位类型                    字节               最小值                                            最大值

   BIT(M)                1-8                BIT(1)                                        BIT(64)

4.日期和时间类型:

    日期和时间类型        字节            最小值                                               最大值

    DATE                        4             1000-01-01                                         9999-12-31

    DATETIME                8             1000-01-01 00:00:00                          9999-12-31 23:59:59

    TIMESTAMP             4             19700101080001                                2038年某个时刻

    TIME                         3             -835:59:59                                      838:59:59

    YEAR                        1             1901                                                     2155

    DATE:表示年月日

    DATETIME:表示年月日时分秒

    TIMESTAMP :需要经常插入或者更新日期为当前系统时间(与实际时区对应)

    TIME:表示时分秒

    YEAR:表示年份

5.字符串类型:

    CHAR系列字符串类型                字节                描述

    CHAR(M)                                M            M为0〜255之间的整数

     VARCHAR(M)                        M            M为0~65535之间的整数

    CHAR和VARCHAR用于储存少量字符串(只能存字符数据)

    

    TEXT系列字符串类型                字节                                        描述

    TINYTEXT                             0~255的长度                        为+2个字节

    TEXT                                    0〜65535值的长度                为+2个字节

    MEDIUMTEXT                      0~167772150值的长度        为+3个字节

    LONGTEXT                           0~4294967295值的长度      为+4个字节


    BINARY系列字符串类型            字节                                        描述

    BINARY(M)                            M                                允许长度为0 - M

    VARBINARY(M)                     M                                允许长度为0 - M

    与CHAR和VARCHAR非常相似,但是可以储存例如图片,音乐或者视频文件等二进制数据,如果存储时经常发生变化则选择VARBINARY类型,否则选择后者


    BLOB系列字符串类型                字节

    TINYBLOB                              0~255

    BLOB                                      0〜2 ^ 16

    MEDIUMBLOB                        0~2 ^ 24

    LONGBLOB                             0〜2 ^ 32

    与TEXT系列非常相似,前者可以存储二进制数据(例如图片,音乐或者视频文件),后者只能存储字符数据

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转载自blog.csdn.net/qq_38386085/article/details/80575504