Query for latest data from updated date timestamp - sql

Question

I just want to get the latest record from my table based on my updated timstamp data, because I want to run this query in my crontab. How can I always get the latest updated data from my query? This is my query:
select
x.updated as updated,
x.data_a->>'custom1' as mch_group,
x.data_a->>'custom2' as mch_name,
x.data_a->>'custom3' as mch_id,
x.data_a->'simAuxFieldsDTO'->>'custom4' as terminal_id,
x.data_a->>'msisdn' as msisdn,
x.data_a->>'simId' as sim_id,
x.data_a->>'acctName' as acct_name,
x.data_a->>'activationDate' as activation_date,
x.data_a->>'inSession' as in_session,
x.data_a->>'sessionType' as session_type,
x.data_a->>'statusNameDisplay' as status_name_display,
x.data_a->>'monthToDateDataUsageMB' as month_todate_data_usage,
x.data_a->>'linePayStatus' as line_pay_status,
x.data_a->>'iccid' as iccid,
x.data_a->>'monthToDateSmsUsage' as month_todate_sms_usage,
x.data_a->>'monthToDateVoiceUsage' as month_todate_voice_usage,
x.data_a->>'overageLimitReached' as overage_limit_reached,
x.data_a->>'termStartDate' as term_startdate,
x.data_a->>'termEndDate' as term_enddate,
x.data_a->>'migratedSim' as migrated_sim
from (
select jsonb_array_elements(a.data_a) as data_a, a.updated as updated
from (
select updated, json_data -> 'data' as data_a
from tcash_edc_json
where updated > TO_TIMESTAMP('2018-09-21 03:02:00','YYYY-MM-DD HH:MI:SS')
)a
) x;

Answer 1

try replacing the where conditions with order by and limit:
instead of this:
where updated > TO_TIMESTAMP('2018-09-21 03:02:00','YYYY-MM-DD HH:MI:SS')
this:
order by updated desc limit 1

Answer 2

You can try to get max(updated) and then do the select where updated = max (updated)