query execution time for last 24 hours in PostgreSQL

Can you please let me know anyone how to get each query execution time from last 24 hours in PostgreSQL 

I tried the below query but giving the wrong information.

SELECT sa.client_addr,
sa.usename,
sa.datname,
sa.state,
sa.query,
sa.query_start,
EXTRACT (EPOCH FROM (current_timestamp sa.query_start)) AS execution_time_seconds
FROM pg_stat_activity sa
WHERE sa.query_start >= current_timestamp interval '24 hours';

Thanks,

Nikhil,

PostgreSQL DBA,

8074430856.