如何在PostgreSQL中减去没有时区的时间戳

Question

I'm currently using PostgreSQL 8.4 and need to substract from now() date on day. What I tried is now() - 1 and it didn't work. Although that page said that we could use operator - to perform operations on date. More preciseli I recieved

ERROR:  operator does not exist: timestamp with time zone - integer

Any ideas?

Answer 1

PostgreSQL can't use mathematical functions directly I think. But we can use date function such interval function in PostgreSQL will solve your problem.

Try below subtract eg:

select interval '2 day' - interval '1 day';
select now() - interval '1' ;

You can also refer to PostgreSQL 8.4 documentation.

http://www.postgresql.org/docs/8.4/static/functions-datetime.html