Default Keyword In MySQL

In MySQL, The DEFAULT keyword is used to specify a default value for a column when a new record is inserted into a table, and the value for that column is not provided in the INSERT statement.

Default Syntax In MySQL Table:

CREATE TABLE tableName (
    columnName1 data_type DEFAULT default_value,
    columnName2 data_type DEFAULT default_value,
);

In the above command, we have declared "columnName1", and "columnName2" as column names.
`data_type` is the data type of the column.
`default_value` is the default value assigned to the column.

Create Table With DEFAULT KEYWORD In MySQL:

Using the below command, we are creating the table named `products` with columns such as `product_id`, `product_name`, `product_category`, `product_price` and `product_added_date`

Example:

CREATE TABLE products (
    product_id INT PRIMARY KEY,
    product_name VARCHAR(50),
    product_category VARCHAR(50),
    product_price INT DEFAULT 300,
    product_added_date DATE DEFAULT CURRENT_DATE
);

In `product_added_date` and `product_price` we have added a DEFAULT KEYWORD so while inserting a new record in the table and no value is provided during an INSERT statement, then `product_price` and `product_added_date` column will column default values.

ADD new Record in MySQL Table using DEFAULT Keyword:

So, Now if we try to insert data into the table, if we don't specify a value for a column with a default, the default value will be used.

Example:

INSERT INTO products (product_id, product_name, category) VALUES (pro1, 'iPad', 'GADGETS');

Now Output will be `product_added_date` will be set to the current date (as per the default), and the `price` will be set to 300 (as per the default).

Update Existing Record using DEFAULT Keyword In MySQL:

We can also use the DEFAULT keyword when updating existing records in the table.

Example:

UPDATE products SET price = DEFAULT WHERE product_id = 'pro1';

This will set the `price` column back to its default value for the specified record.

Add DEFAULT KEYWORD in Existing MySQL Table:

using the below command, we can add DEFAULT KEYWORD to an Existing Table in SQL.

Example:

ALTER TABLE products
ALTER COLUMN isOutOfStock SET DEFAULT 1;

In the above command, we have added a DEFAULT Value in Integer where `0` will be considered as `false` and `1` will be considered as `true` value

<-- Unique Key

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