How can I convert from Double Precision to Bigint with PostgreSQL? I need to convert a value of Double Precision to Bigint with PostgreSQL. How can I do that?

I have tried with to_bigint(myvalue) but that function didn't exist.
There are two ways to typecast in Postgres:

You either do it the SQL standard way: 

select cast(3.141593 as bigint);


or you could use the Postgres-specific cast operator: :: 

select (3.141593 :: bigint);


You might also want to consider the various rounding functions.