Postgres manually alter sequence

Question

I\'m trying to set a sequence to a specific value.

SELECT setval(\'payments_id_seq\'), 21, true

This gives an error:

Answer 1

Use select setval('payments_id_seq', 21, true);

setval contains 3 parameters:

• 1st parameter is sequence_name
• 2nd parameter is Next nextval
• 3rd parameter is optional.

The use of true or false in 3rd parameter of setval is as follows:

SELECT setval('payments_id_seq', 21);           // Next nextval will return 22
SELECT setval('payments_id_seq', 21, true);     // Same as above 
SELECT setval('payments_id_seq', 21, false);    // Next nextval will return 21

The better way to avoid hard-coding of sequence name, next sequence value and to handle empty column table correctly, you can use the below way:

SELECT setval(pg_get_serial_sequence('table_name', 'id'), coalesce(max(id), 0)+1 , false) FROM table_name;

where table_name is the name of the table, id is the primary key of the table