how to restart the id index in postgresql code example

Example 1: postgresql reset auto_increment index

-- Change the starting value of the sequence

ALTER SEQUENCE project_id_seq RESTART 3000;

-- Same but dynamic :

SELECT SETVAL('project_id_seq', (SELECT MAX(id) + 1 FROM project));

Example 2: postgresql reset serial counter after deleting content

ALTER SEQUENCE product_id_seq RESTART WITH 1453