How to convert date to the date of the Monday of the date in SQL?

Question

Assume 2022-10-01 and 2022-10-8 are Monday, and the original table looks like this:

Date	Value
2022-10-03	x
2022-10-04	y
2022-10-09	z

I want to convert it to

Date	Value
2022-10-01	x
2022-10-01	y
2022-10-08	z

Is there any simple ways to do this? Thanks!

I tried look up but seems not finding anything neat solutions

Answer 1

You can use the date_trunc function. For example:

SELECT date_trunc('week', dt)
FROM (
    VALUES DATE '2022-12-01'
) t(dt)

output:

   _col0
------------
 2022-11-28
(1 row)