how to change the first day of the week in PostgreSQL

Question

I need to change the week start date from Monday to Saturday in PostgreSQL. I have tried SET DATEFIRST 6; but it doesn\'t work in PostgreSQL. Plea

Answer 1

You can just add +x, where x is the offset between postgres dow and what you want to achieve.

For example:

You want Sunday to be the first day of the week. 2018-06-03 is a Sunday and you want to extract the dow of it:

SELECT EXTRACT(DOW FROM DATE '2018-06-03')+1;

returns 1

That is probably the reason why postgres dow yields 0 for Sunday. Would it be 7, then

SELECT EXTRACT(DOW FROM DATE '2018-06-03')+1; 

would return 8.