Understanding Different Timestamp Methods in PostgreSQL

There are various methods to retrieve the current time in PostgreSQL. These methods include:

1. The value current_timestamp

2. The function now()

3. The function clock_timestamp()

Here are some examples using these methods in SQL code snippets:

1INSERT INTO person (id, name, created_at) VALUES ('33333333-3333-3333-3333-333333333005', 'Max' , current_timestamp);
2INSERT INTO person (id, name, created_at) VALUES ('33333333-3333-3333-3333-333333333005', 'Max' , now());
3INSERT INTO person (id, name, created_at) VALUES ('33333333-3333-3333-3333-333333333005', 'Max' , clock_timestamp());

All these methods will insert a timestamp into the database, but they work somewhat differently.

current_timestamp is a value defined in Standard SQL. You can find more standard values in the PostgreSQL manual.

Both now() and clock_timestamp() are PostgreSQL functions. The main difference between them is that now() adds the time at the start of the transactions, while clock_timestamp() inserts the time at the execution of the statement.