What is the SQL query to find the number of customers placing orders in each month?

 To find the number of customers placing orders in each month, you would need a table that records the orders placed by customers, such as an orders table. This table would typically include fields such as order_id, customer_id, and order_date.

Assuming the table is named orders and contains these columns:

• order_id: A unique identifier for each order.
• customer_id: A unique identifier for each customer.
• order_date: The date the order was placed.

The SQL query to count the number of unique customers placing orders each month would look like this:

SELECT
    EXTRACT(YEAR FROM order_date) AS year,
    EXTRACT(MONTH FROM order_date) AS month,
    COUNT(DISTINCT customer_id) AS num_customers
FROM
    orders
GROUP BY
    EXTRACT(YEAR FROM order_date),
    EXTRACT(MONTH FROM order_date)
ORDER BY
    year, month;

Explanation:

• EXTRACT(YEAR FROM order_date): Extracts the year from the order_date column.
• EXTRACT(MONTH FROM order_date): Extracts the month from the order_date column.
• COUNT(DISTINCT customer_id): Counts the number of unique customers who placed orders in that month.
• GROUP BY: Groups the results by year and month.
• ORDER BY: Orders the results first by year and then by month to ensure chronological order.

Example Output:

year	month	num_customers
2023	1	150
2023	2	180
2023	3	200
...	...	...

This query provides the number of unique customers who placed orders for each month.