How to set the default value to 0 in mysql

Setting the default value of a column to 0 in MySQL can be achieved by the following methods: use the DEFAULT keyword when creating a table, for example: CREATE TABLE user (id INT DEFAULT 0); use the ALTER TABLE statement when modifying the table , for example: ALTER TABLE user ALTER COLUMN age SET DEFAULT 0;

How to set the default value to 0 in MySQL

In MySQL , you can set the default value of a column to 0 by using the DEFAULT keyword when creating or modifying a table.

Set default value when creating table

When creating table, you can use the following syntax to set the default value of a column to 0:

<code class="sql">CREATE TABLE table_name (
  column_name DATATYPE DEFAULT 0
);</code>

For example:

<code class="sql">CREATE TABLE users (
  id INT AUTO_INCREMENT PRIMARY KEY,
  name VARCHAR(255),
  age INT DEFAULT 0
);</code>

Set default values ​​when modifying tables

To modify the default values ​​of columns of an existing table, you can use the following syntax:

<code class="sql">ALTER TABLE table_name ALTER COLUMN column_name SET DEFAULT 0;</code>

For example:

<code class="sql">ALTER TABLE users ALTER COLUMN age SET DEFAULT 0;</code>

Important notes

• Default values ​​can only be set on the following data types: INTEGER, DECIMAL, FLOAT, DOUBLE , CHAR, VARCHAR, BINARY, and VARBINARY.
• If you do not set a default value explicitly, the default value for a numeric column will be NULL.
• Even if a default value is specified, the value can still be overridden when inserting records.

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