Table of contents
Preface: Review MySQL knowledge
The punctuation marks of all SQL statements are half-width symbols.
The contents in [ ] are optional parameters
Experimental environment: win10
Log in to MySQL
Start the MySQL server
Open the win10 command prompt (win+R) and enter cmd
Then enter mysql -uroot -p
Enter your password to log in to the MySQL server
1.Create database
Create database m1
①CREATE DATABASE `m1`;
②CREATE DATABASE IF NOT EXISTS `m1`;
(When using ①, if the database m1 already exists in the database, an error will be reported (error message: Can't create database 'm1' ; database exists))
(The meaning of the statement in ② is: if the database m1 does not exist in MySQL, create the m1 database; if already exists in the database m1 in MySQL, ignore this statement , no more database will be created)
2. Create an m2 database using the utf8 character set and with proofreading rules.
CREATE DATABASE `m1` CHARACTER SET 'utf8' COLLATE 'utf8_bin';
View database
View all databases SHOW DATABASES;
View the specified database SHOW CREATE DATABASE database name;
Select (use) database USE database name;
View the currently used database SELECT DATABASE();
Modify database
Modify the encoding method of the database (this statement cannot modify the database name):
ALTER DATABASE database name DEFAULT CHARACTER SET encoding method COLLATE encoding method_bin;
Example: Modify the encoding method of m1 to gbk
ALTER DATABASE `m1` CHARACTER SET gbk;
Delete database
①DROP DATABASE database name;
②DROP DATABASE IF EXISTS database name;
Example: Delete database m1
DROP DATABASE IF EXISTS `m1`;
(The meaning of the statement in ② is: if the database m1 exists in MySQL, delete the database; if the database m1 does not exist in MySQL, ignore the statement and do not delete the database)
2. Create a data table
CREATE TABLE [IF NOT EXISTS] table name
(
field name field type integrity constraints,
Field name data type integrity constraints,
Field name data type integrity constraints
);
View datasheet
(DESC is the abbreviation of DESCRIBE)
View all tables in the database SHOW TABLES;
View the creation statement of the data table SHOW CREATE TABLE data table name;
View data table field information DESC data table name;
View the data table structure SHOW [FULL] COLUMNS FROM database name.data table name;
Modify data table
Modify the data table name:
①ALTER TABLE old table name RENAME [TO/AS] new table name;
②RENAME TABLE old table name 1 TO new table name 1 [, old table name 2 TO new table name 2];
Modify field name:
ALTER TABLE table name CHANGE old field name new field name new field type [attribute];
Modify field data type:
ALTER TABLE table name MODIFY field name data type;
Modify the field arrangement position:
①Adjust field 1 to the first column using FIRST
ALTER TABLE table name MODIFY field name 1 data type FIRST;
②Adjust field 1 to a position other than the first column, use AFTER field name 2
ALTER TABLE table name MODIFY field name 1 data type AFTER field name 2;
New fields:
①Add a field
ALTER TABLE table name ADD field name data type [constraints];
②Add multiple fields at one time (for example, add 2 fields)
ALTER TABLE table name ADD field name data type [constraints], ADD field name data type [constraints];
③Add a new field before or after a specified field
ALTER TABLE table name ADD field name data type [constraints] [BEFORE/AFTER existing field name];
Delete fields:
ALTER TABLE table name DROP field name;
Delete data table:
①DROP TABLE table name 1[, table name 2];
②DROP TABLE IF EXISTS table name 1[, table name 2];