MySQL data type

Data types in MySQL:

Integer type:

#查看int整数型的帮助.

Mysql>? Intname: ' INT ' description:int[(M)] [UNSIGNED] [zerofill]a normal-size Integer. The signed range is-2147483648 to 2147483647.The unsigned range are 0 to 4294967295.URL:HTTP://DEV.MYSQL.COM/DOC/REFMAN/5 .6/en/numeric-type-overview.html

#查看创建数据库的帮助, this discovery is not recognized using schema.

mysql> help create Schemanothing foundplease try-to-run ' help Contents ' for a list of all accessible topics

#可以使用help? \h three options to see Help.

mysql> help create DatabaseName: ' Create database ' Description:Syntax:CREATE {database | SCHEMA} [IF not EXISTS] db_name [create_specification] ... create_specification: [DEFAULT] CHARACTER SET [=] charset_ name | [DEFAULT] COLLATE [=] collation_namecreate database creates a database with the given name. To use thisstatement, you need the CREATE privilege for the database. Createschema is a synonym for CREATE DATABASE. Url:http://dev.mysql.com/doc/refman/5.6/en/create-database.html

Mysql>? Tinyintname: ' TINYINT ' description:tinyint[(M)] [UNSIGNED] [zerofill]a very small integer. The signed range is-128 to 127. The Unsignedrange is 0 to 255.url:http://dev.mysql.com/doc/refman/5.6/en/numeric-type-overview.html

mysql> \h intname: ' INT ' description:int[(M)] [UNSIGNED] [zerofill]a normal-size Integer. The signed range is-2147483648 to 2147483647.The unsigned range are 0 to 4294967295.URL:HTTP://DEV.MYSQL.COM/DOC/REFMAN/5 .6/en/numeric-type-overview.html

Floating-point types:

M is the total number of digits, and D is the number of digits after the decimal point.

Float (m,d)

String type:

Char (m) m bytes, 0-255

varchar (M) l+1 bytes, 0-65535

Date Time Type:

Time

Date

Datetime

Year

#查看mysql有那些存储引擎 (default is InnoDB)

mysql> show engines;+--------------------+---------+--------------------------------------------- -------------------+--------------+------+------------+| engine              | Support | Comment                                                           | transactions |  xa   | savepoints |+--------------------+---------+---------------------------- ------------------------------------+--------------+------+------------+| memory              | yes     | hash  based, stored in memory, useful for temporary tables      |  no           | no   | no          | |  csv                |  YES     | CSV storage engine                                                | NO           | NO    | no         | |  MRG_MYISAM         | YES      | Collection of identical MyISAM tables                            | no           | no   |  no         | |  BLACKHOLE          | YES      | /dev/null storage engine  (anything you write to it  Disappears)  | NO           | NO    | no         | |  MyISAM             | YES      | MyISAM storage engine                                            | no            | NO   | NO          | |  FEDERATED          | NO       | Federated MySQL storage engine                                   | NULL          | null | null       | |  ARCHIVE            | YES      | archive storage engine                                           | NO            | NO   | NO          | |  InnoDB             | DEFAULT  | supports transactions, row-level locking, and foreign keys      | YES          | YES   | yes        | |  PERFORMANCE_SCHEMA | YES     | Performance Schema                                               |  no           | no   | no          |+--------------------+---------+----------------------------- -----------------------------------+--------------+------+------------+9 rows in set  (0.00  SEC)

#查看显示支持的存储引擎的信息:

mysql> show variables like  ' have% '; +----------------------+----------+| variable_ name        | value    |+-------------------- --+----------+| have_compress        | yes       | |  have_crypt           | YES       | |  have_dynamic_loading | yes      | |  have_geometry        | YES       | |  have_openssl         | disabled | |  have_profiling       | yes      | |  have_query_cache     | yes      | |  have_rtree_keys      | yes      | |  have_ssl             | disabled  | |  have_symlink         | disabled |+--------------- -------+----------+10 rows in set  (0.00 sec)

This article is from the "LINUX Super Dream" blog, make sure to keep this source http://215687833.blog.51cto.com/6724358/1905770

MySQL data type