Postgres: jak przekonwertować z epoki unixa do tej pory?

Question

W oświadczeniu podano datę i godzinę.

Jak zmodyfikować instrukcję tak, aby zwracała tylko datę?

SELECT to_timestamp(TRUNC(CAST(epoch_ms AS bigint )/1000)); 

Answer 1

/* Current time */ 
select now(); 

/* Epoch from current time; 
    Epoch is number of seconds since 1970-01-01 00:00:00+00 */ 
select extract(epoch from now()); 

/* Get back time from epoch */ 
-- Option 1 - use to_timestamp function 
select to_timestamp(extract(epoch from now())); 
-- Option 2 - add seconds to 'epoch' 
select timestamp with time zone 'epoch' 
     + extract(epoch from now()) * interval '1 second'; 

/* Cast timestamp to date */ 
-- Based on Option 1 
select to_timestamp(extract(epoch from now()))::date; 
-- Based on Option 2 
select (timestamp with time zone 'epoch' 
      + extract(epoch from now()) * interval '1 second')::date; 

/* For column epoch_ms */ 
select to_timestamp(extract(epoch epoch_ms))::date; 

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