1. INSERT

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Introduction to the MySQL INSERT statement

The INSERT statement allows you to insert one or more rows into a table. The following illustrates the syntax of the INSERT statement:

INSERT INTO table_name(column1, column2,...)
VALUES (value1, value2,...);

In this syntax,

First, specify the table name and a list of comma-separated columns inside parentheses after the INSERT INTO clause.
Then, put a comma-separated list of values of the corresponding columns inside the parentheses following the VALUES keyword.

When using the INSERT statement, you need to ensure that the number of columns matches the number of values.

Additionally, you need to specify that the positions of columns correspond precisely to the positions of their corresponding values.

To insert multiple rows into a table using a single INSERT statement, you use the following syntax:

INSERT INTO table(column1, column2,...)
VALUES
  (value1, value2,...),
  (value1, value2,...),
  ...
  (value1, value2,...);

In this syntax, rows are separated by commas in the VALUES clause.

MySQL INSERT statement examples

DROP TABLE IF EXISTS tasks;

CREATE TABLE tasks (
  task_id INT AUTO_INCREMENT PRIMARY KEY, 
  title VARCHAR(255) NOT NULL, 
  start_date DATE, 
  due_date DATE, 
  priority TINYINT NOT NULL DEFAULT 3, 
  description TEXT
);

1) Basic MySQL INSERT statement example

The following statement inserts a new row into the tasks table:

INSERT INTO tasks(title, priority)
VALUES('Learn MySQL INSERT Statement', 1);

Output:

1 row(s) affectedCode language: SQL (Structured Query Language) (sql)

The output indicates that the statement inserted one row into the tasks table successfully.

In this example, we specified values for the title and priority columns only. For other columns, MySQL uses the default values.

The task_id column is an AUTO_INCREMENT column, meaning that MySQL generates a sequential integer whenever a row is inserted into the table.

The start_date, due_date, and description columns use NULL as the default value. Therefore, MySQL insert NULL into these columns if you don’t specify their values in the INSERT statement.

The following retrieves data from the tasks table:

SELECT * FROM tasks;Code language: SQL (Structured Query Language) (sql)

Output:

+---------+------------------------------+------------+----------+----------+-------------+
| task_id | title                        | start_date | due_date | priority | description |
+---------+------------------------------+------------+----------+----------+-------------+
|       1 | Learn MySQL INSERT Statement | NULL       | NULL     |        1 | NULL        |
+---------+------------------------------+------------+----------+----------+-------------+
1 row in set (0.00 sec)

2) Inserting rows using default value example

If you want to insert a default value into a column, you have two ways:

Ignore both the column name and value in the INSERT statement.
Specify the column name in the INSERT INTO clause and use the DEFAULT keyword in the VALUES clause.

The following example demonstrates the second way:

INSERT INTO tasks(title, priority)
VALUES('Understanding DEFAULT keyword', DEFAULT);Code language: SQL (Structured Query Language) (sql)

In this example, we specified the value for title and priority columns.

Because the default value for the column priority is 3 as declared in the table definition, the statement inserts number 3 into the priority column.

priority TINYINT NOT NULL DEFAULT 3Code language: SQL (Structured Query Language) (sql)

The following statement returns the contents of the tasks table after the insert:

SELECT * FROM tasks;Code language: SQL (Structured Query Language) (sql)

Output:

+---------+-------------------------------+------------+----------+----------+-------------+
| task_id | title                         | start_date | due_date | priority | description |
+---------+-------------------------------+------------+----------+----------+-------------+
|       1 | Learn MySQL INSERT Statement  | NULL       | NULL     |        1 | NULL        |
|       2 | Understanding DEFAULT keyword | NULL       | NULL     |        3 | NULL        |
+---------+-------------------------------+------------+----------+----------+-------------+
2 rows in set (0.00 sec)

3) Inserting dates into the table example

To insert a literal date value into a column, you use the following format:

'YYYY-MM-DD'Code language: SQL (Structured Query Language) (sql)

In this format:

YYYY represents a four-digit year e.g., 2018.
MM represents a two-digit month e.g., 01, 02, and 12.
DD represents a two-digit day e.g., 01, 02, 30.

The following statement inserts a new row to the tasks table with the start and due date values:

INSERT INTO tasks(title, start_date, due_date)
VALUES ('Insert date into table', '2018-01-09', '2018-09-15');Code language: SQL (Structured Query Language) (sql)

Output:

+---------+-------------------------------+------------+------------+----------+-------------+
| task_id | title                         | start_date | due_date   | priority | description |
+---------+-------------------------------+------------+------------+----------+-------------+
|       1 | Learn MySQL INSERT Statement  | NULL       | NULL       |        1 | NULL        |
|       2 | Understanding DEFAULT keyword | NULL       | NULL       |        3 | NULL        |
|       3 | Insert date into table        | 2018-01-09 | 2018-09-15 |        3 | NULL        |
+---------+-------------------------------+------------+------------+----------+-------------+
3 rows in set (0.00 sec)Code language: PHP (php)

It is possible to use expressions in the VALUES clause. For example, the following statement adds a new task using the current date for the start date and due date columns:

INSERT INTO tasks(title, start_date, due_date)
VALUES
  (
    'Use current date for the task',
    CURRENT_DATE(),
    CURRENT_DATE()
  );Code language: SQL (Structured Query Language) (sql)

In this example, we used the CURRENT_DATE() function as the values for the start_date and due_date columns. Note that the CURRENT_DATE() function is a date function that returns the current system date.

Here are the contents of the tasks table after insert:

+---------+-------------------------------+------------+------------+----------+-------------+
| task_id | title                         | start_date | due_date   | priority | description |
+---------+-------------------------------+------------+------------+----------+-------------+
|       1 | Learn MySQL INSERT Statement  | NULL       | NULL       |        1 | NULL        |
|       2 | Understanding DEFAULT keyword | NULL       | NULL       |        3 | NULL        |
|       3 | Insert date into table        | 2018-01-09 | 2018-09-15 |        3 | NULL        |
|       4 | Use current date for the task | 2023-12-28 | 2023-12-28 |        3 | NULL        |
+---------+-------------------------------+------------+------------+----------+-------------+
4 rows in set (0.00 sec)

4) Inserting multiple rows example

The following statement inserts three rows into the tasks table:

INSERT INTO tasks(title, priority)
VALUES
	('My first task', 1),
	('It is the second task',2),
	('This is the third task of the week',3);Code language: SQL (Structured Query Language) (sql)

In this example, each row of data is specified as a list of values in the VALUESclause.

MySQL returns the following message:

3 row(s) affected Records: 3  Duplicates: 0  Warnings: 0Code language: SQL (Structured Query Language) (sql)

It means that the three rows have been inserted successfully with no duplicates or warnings.

SELECT * FROM tasks;Code language: SQL (Structured Query Language) (sql)

The table tasks has the following data:

+---------+------------------------------------+------------+------------+----------+-------------+
| task_id | title                              | start_date | due_date   | priority | description |
+---------+------------------------------------+------------+------------+----------+-------------+
|       1 | Learn MySQL INSERT Statement       | NULL       | NULL       |        1 | NULL        |
|       2 | Understanding DEFAULT keyword      | NULL       | NULL       |        3 | NULL        |
|       3 | Insert date into table             | 2018-01-09 | 2018-09-15 |        3 | NULL        |
|       4 | Use current date for the task      | 2023-12-28 | 2023-12-28 |        3 | NULL        |
|       5 | My first task                      | NULL       | NULL       |        1 | NULL        |
|       6 | It is the second task              | NULL       | NULL       |        2 | NULL        |
|       7 | This is the third task of the week | NULL       | NULL       |        3 | NULL        |
+---------+------------------------------------+------------+------------+----------+-------------+
7 rows in set (0.00 sec)

5) Dealing with auto-increment column

Suppose you have a table that has an auto-increment column:

CREATE TABLE t(
   id INT AUTO_INCREMENT PRIMARY KEY
);

The following statement insert a new row into the t table, which uses the generated value:

INSERT INTO t VALUES();

In this statement, we don’t specify any column after the table name and any values inside the VALUES() clause.

Here’s the contents of the t table:

SELECT * FROM t;

Output:

+----+
| id |
+----+
|  1 |
+----+
1 row in set (0.00 sec)Code language: JavaScript (javascript)