如何将bigint字段格式化为Postgresql中的日期？

TO_CHAR(TO_TIMESTAMP(bigint_field / 1000), 'DD/MM/YYYY HH24:MI:SS')

select to_timestamp(20120822193532::text, 'YYYYMMDDHH24MISS')

to_timestamp(to_char(20120822193532, '9999-99-99 99:99:99'),'YYYY-MM-DD HH24:MI:SS')

to_char(20120822193532, '9999-99-99 99:99:99')

to_timestamp('2012-08-22 19:35:32','YYYY-MM-DD HH24:MI:SS')

CREATE TABLE table2 AS SELECT to_timestamp(to_char(tb1.date, '9999-99-99 99:99:99'),'YYYY-MM-DD HH24:MI:SS') AS realDate FROM table1 AS tb1; 

ALTER TABLE table2 ALTER realDate SET DATA TYPE timestamp USING realDate;