What is the way to write the table creation statement in mysql?

In MySQL, you can use the "CREATE TABLE" statement to create a table, which is written as: "CREATE TABLE table name ([table definition option])[table option][partition option];", where "[ Table definition option]" is in the format of "column name 1 type 1 [,…] column name n type n".

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After creating the database, the next step is to create the database Create a data table. The so-called creating a data table refers to creating a new table in the already created database.

The process of creating a data table is the process of specifying the attributes of the data columns, and it is also the process of implementing data integrity (including entity integrity, referential integrity and domain integrity) constraints.

Basic syntax

In MySQL, you can use the CREATE TABLE statement to create a table. The syntax format is:

CREATE TABLE <表名> ([表定义选项])[表选项][分区选项];

Among them, the format of [Table Definition Options] is:

<列名1> <类型1> [,…] <列名n> <类型n>

The CREATE TABLE command syntax is more, which mainly consists of table creation definition (create-definition), Composed of table options (table-options) and partition options (partition-options).

Here we first describe a simple example of creating a new table, and then focus on some main syntax knowledge points in the CREATE TABLE command.

The main syntax and usage instructions of the CREATE TABLE statement are as follows:

• CREATE TABLE: used to create a table with a given name, you must have table CREATE permissions.

• : Specifies the name of the table to be created, given after CREATE TABLE, and must comply with the identifier naming rules. The table name is specified as db_name.tbl_name to create the table in a specific database. It can be created this way regardless of whether there is a current database. db-name can be omitted when creating a table in the current database. If you use quoted distinguished names, the database and table names should be quoted separately. For example, 'mydb'.'mytbl' is legal, but 'mydb.mytbl' is not.

: Table creation definition, consisting of column name (col_name), column definition (column_definition), and possible null value specifications, integrity constraints, or table indexes composition.

• By default, the table is created in the current database. If the table already exists, there is no current database, or the database does not exist, an error will occur.

Tip: When using CREATE TABLE to create a table, you must specify the following information:

• The name of the table to be created is not size sensitive When writing, you cannot use keywords in the SQL language, such as DROP, ALTER, INSERT, etc.

• The name and data type of each column (field) in the data table. If you create multiple columns, separate them with commas.

Create a table in the specified database

The data table belongs to the database, before creating the data table , you should use the statement "USE" to specify which database the operation is to be performed in. If no database is selected, a No database selected error will be thrown.

Example

Create the employee table tb_emp1 with the structure as shown in the following table.

Field name	Data type	Remarks
id	INT(ll)	Employee number
name	VARCHAR(25)	Employee name
deptld	INT(ll)	Department number
salary	FLOAT	Salary

#Select the database test_db to create the table, create the tb_emp1 data table, and enter the SQL statement and running results as shown below.

mysql> USE test_db;
Database changed
mysql> CREATE TABLE tb_emp1
    -> (
    -> id INT(11),
    -> name VARCHAR(25),
    -> deptId INT(11),
    -> salary FLOAT
    -> );
Query OK, 0 rows affected (0.37 sec)

After the statement is executed, a data table named tb_emp1 is created. Use the SHOW TABLES; statement to check whether the data table is created successfully, as shown below.

mysql> SHOW TABLES;
+--------------------+
| Tables_in_test_db  |
+--------------------+
| tb_emp1            |
+--------------------+
1 rows in set (0.00 sec)

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