how can i get the all data from postgresql thats from the current day, between the hours of 00:00:00 and 11:59:59? - postgresql

Question

very new to the backend as well as all things postgresql, at the moment all ive been able to do is
SELECT * FROM nutrition WHERE timestamp >= (extract(epoch from now())::bigint * 1000) - 86400000 AND timestamp <= (extract(epoch from now())::bigint * 1000) + 86400000
in the frontend using js, im using Date.now() to store the timestamp in the DB.
timestamp is a column in my db thats logging the unix time in bigint format in which the food was logged. I want to get all the data from the current day from the hours beteen 12 AM midnight, and 11:59 PM. thanks.
for example, the last item i logged was last night at 10pm (1663995295337 UNIX time) so the data shouldnt include it.
show timezone returns;
America/Los_Angeles
Solution below --------------------------------------------------------------------
const today = new Date();
const beginningOfDay = today.setUTCHours(7, 0, 0, 0);
const endOfDay = today.setUTCHours(30, 59, 59, 99);
switch (method) {
case "GET":
try {
const text = `
select
*
from
nutrition
where
timestamp
between ${beginningOfDay} and ${endOfDay}`
this was the solution i was looking for, thanks for the help. sorry if i wasnt descriptive enough.

Answer 1

Assuming that by Unix time you mean epoch.
select extract(epoch from now());
extract
-------------------
1664038032.392004
select to_timestamp(1664038032.392004);
to_timestamp
--------------------------------
09/24/2022 09:47:12.392004 PDT
select
*
from
some_table
where
to_timestamp(1664038032.392004)
between
current_date + '00:00:00'::time AND current_date + '23:59:59'::time
UPDATE
Using timestamptz field in Postgres and an ISO datetime string from Javascript in order to properly deal with time zone.
create table tsz_test(id integer, tsz_fld timestamptz);
--In Web frontend today = new Date().toISOString(); "2022-09-24T20:57:05.830Z"
insert into
tsz_test
values (1, '2022-09-24T20:57:05.830Z'), (2, '2022-09-25T08:57:05.830Z');
select * from tsz_test ;
id | tsz_fld
----+----------------------------
1 | 09/24/2022 13:57:05.83 PDT
2 | 09/25/2022 01:57:05.83 PDT
--Borrowing from #a_horse_with_no_name answer
select * from tsz_test where tsz_fld::date = '09/24/2022'::date;
id | tsz_fld
----+----------------------------
1 | 09/24/2022 13:57:05.83 PDT

Answer 2

You can convert your "unix timestamp" to a date, then compare it with "today":
where to_timestamp("timestamp")::date = current_date
This assumes that your column named "timestamp" is not really a timestamp
If the column doesn't actually store seconds (which would be a unix epoch), but milliseconds you need to_timestamp("timestamp"/1000)::date instead (another source of problems that wouldn't exist if you had used a proper timestamptz or at least timestamp data type).