What is the first day of the month in MySQL?

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You can use the following syntax to get the first day of the month for a given date in MySQL:

SELECT sales_date, DATE_ADD(sales_date, INTERVAL -DAY(sales_date)+1 DAY)
FROM sales;

This particular example creates a new column that contains the first day of the month for the corresponding date in the sales_date column of the table named sales.

The following example shows how to use this syntax in practice.

Example: How to Get First Day of Month in MySQL

Suppose we have the following table named sales that contains information about sales made at various grocery stores on various dates:

-- create table 
CREATE TABLE sales (
  store_ID INT PRIMARY KEY,
  item TEXT NOT NULL,
  sales_date DATE NOT NULL
);

-- insert rows into table
INSERT INTO sales VALUES (0001, 'Oranges', '2024-02-10');
INSERT INTO sales VALUES (0002, 'Apples', '2024-11-25');
INSERT INTO sales VALUES (0003, 'Bananas', '2024-06-30');
INSERT INTO sales VALUES (0004, 'Melons', '2024-01-14');
INSERT INTO sales VALUES (0005, 'Grapes', '2024-05-19');

-- view all rows in table
SELECT * FROM sales;

Output:

+----------+---------+------------+
| store_ID | item    | sales_date |
+----------+---------+------------+
|        1 | Oranges | 2024-02-10 |
|        2 | Apples  | 2024-11-25 |
|        3 | Bananas | 2024-06-30 |
|        4 | Melons  | 2024-01-14 |
|        5 | Grapes  | 2024-05-19 |
+----------+---------+------------+

Suppose that we would like to select the dates from the sales_date column and create a new column that contains the first day of the month for each corresponding date in the sales_date column.

We can use the following syntax to do so:

SELECT sales_date, DATE_ADD(sales_date, INTERVAL -DAY(sales_date)+1 DAY)
FROM sales;

Output:

+------------+-------------------------------------------------------+
| sales_date | DATE_ADD(sales_date, INTERVAL -DAY(sales_date)+1 DAY) |
+------------+-------------------------------------------------------+
| 2024-02-10 | 2024-02-01                                            |
| 2024-11-25 | 2024-11-01                                            |
| 2024-06-30 | 2024-06-01                                            |
| 2024-01-14 | 2024-01-01                                            |
| 2024-05-19 | 2024-05-01                                            |
+------------+-------------------------------------------------------+

Notice that the dates in the new column represent the first day of the month for the corresponding date in the sales_date column.

If you’d like, you can also use the AS statement to give a specific name to this new column:

SELECT sales_date, DATE_ADD(sales_date, INTERVAL -DAY(sales_date)+1 DAY) AS first_day
FROM sales;

+------------+------------+
| sales_date | first_day  |
+------------+------------+
| 2024-02-10 | 2024-02-01 |
| 2024-11-25 | 2024-11-01 |
| 2024-06-30 | 2024-06-01 |
| 2024-01-14 | 2024-01-01 |
| 2024-05-19 | 2024-05-01 |
+------------+------------+

Notice that the new column is now named first_day, which is much easier to read.

Additional Resources

The following tutorials explain how to perform other common tasks in MySQL:

MySQL: How to Select Rows where Date is Equal to Today