What is the MySQL database creation statement?
Syntax: create database [if not exists] Database name [option]
1. Create database
mysql> create database stu; Query OK, 1 row affected (0.01 sec)
2. When creating a database, the database already exists Error
ERROR 1007 (HY000): Can't create database 'stu'; database exists
When creating the database, determine whether the database exists. If it does not exist, create it
3. Use special characters and keywords as the database name
Use backticks to change the database name Include it. ``
mysql> create database `create` mysql> create database `$%`; Query OK, 1 row affected (0.00 sec)
4. When creating the database, specify the character encoding
mysql> create database yudb charset=gbk;
If no encoding is specified, the database will default to the encoding specified when installing the database
The above is the detailed content of What is the MySQL database creation statement?. For more information, please follow other related articles on the PHP Chinese website!

Hot AI Tools

Undress AI Tool
Undress images for free

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

To display all databases in MySQL, you need to use the SHOWDATABASES command; 1. After logging into the MySQL server, you can execute the SHOWDATABASES; command to list all databases that the current user has permission to access; 2. System databases such as information_schema, mysql, performance_schema and sys exist by default, but users with insufficient permissions may not be able to see it; 3. You can also query and filter the database through SELECTSCHEMA_NAMEFROMinformation_schema.SCHEMATA; for example, excluding the system database to only display the database created by users; make sure to use

To add a primary key to an existing table, use the ALTERTABLE statement with the ADDPRIMARYKEY clause. 1. Ensure that the target column has no NULL value, no duplication and is defined as NOTNULL; 2. The single-column primary key syntax is ALTERTABLE table name ADDPRIMARYKEY (column name); 3. The multi-column combination primary key syntax is ALTERTABLE table name ADDPRIMARYKEY (column 1, column 2); 4. If the column allows NULL, you must first execute MODIFY to set NOTNULL; 5. Each table can only have one primary key, and the old primary key must be deleted before adding; 6. If you need to increase it yourself, you can use MODIFY to set AUTO_INCREMENT. Ensure data before operation

Check whether the MySQL service is running, use sudosystemctlstatusmysql to confirm and start; 2. Make sure that bind-address is set to 0.0.0.0 to allow remote connections and restart the service; 3. Verify whether the 3306 port is open, check and configure the firewall rules to allow the port; 4. For the "Accessdenied" error, you need to check the user name, password and host name, and then log in to MySQL and query the mysql.user table to confirm permissions. If necessary, create or update the user and authorize it, such as using 'your_user'@'%'; 5. If authentication is lost due to caching_sha2_password

Using mysqldump is the most common and effective way to back up MySQL databases. It can generate SQL scripts containing table structure and data. 1. The basic syntax is: mysqldump-u[user name]-p[database name]>backup_file.sql. After execution, enter the password to generate a backup file. 2. Back up multiple databases with --databases option: mysqldump-uroot-p--databasesdb1db2>multiple_dbs_backup.sql. 3. Back up all databases with --all-databases: mysqldump-uroot-p

B-TreeindexesarebestformostPHPapplications,astheysupportequalityandrangequeries,sorting,andareidealforcolumnsusedinWHERE,JOIN,orORDERBYclauses;2.Full-Textindexesshouldbeusedfornaturallanguageorbooleansearchesontextfieldslikearticlesorproductdescripti

UNIONremovesduplicateswhileUNIONALLkeepsallrowsincludingduplicates;1.UNIONperformsdeduplicationbysortingandcomparingrows,returningonlyuniqueresults,whichmakesitsloweronlargedatasets;2.UNIONALLincludeseveryrowfromeachquerywithoutcheckingforduplicates,

You can customize the separator by using the SEPARATOR keyword in the GROUP_CONCAT() function; 1. Use SEPARATOR to specify a custom separator, such as SEPARATOR'; 'The separator can be changed to a semicolon and plus space; 2. Common examples include using the pipe character '|', space'', line break character '\n' or custom string '->' as the separator; 3. Note that the separator must be a string literal or expression, and the result length is limited by the group_concat_max_len variable, which can be adjusted by SETSESSIONgroup_concat_max_len=10000; 4. SEPARATOR is optional

The table can be locked manually using LOCKTABLES. The READ lock allows multiple sessions to read but cannot be written. The WRITE lock provides exclusive read and write permissions for the current session and other sessions cannot read and write. 2. The lock is only for the current connection. Execution of STARTTRANSACTION and other commands will implicitly release the lock. After locking, it can only access the locked table; 3. Only use it in specific scenarios such as MyISAM table maintenance and data backup. InnoDB should give priority to using transaction and row-level locks such as SELECT...FORUPDATE to avoid performance problems; 4. After the operation is completed, UNLOCKTABLES must be explicitly released, otherwise resource blockage may occur.
