Select new or updated records com table in Postgresql

Question

It's possible to get all the new or update records from one table in postgresql by specified date?

something like this:

Select NEW OR UPDATED FROM anyTable WHERE dt_insert or dt_update = '2015-01-01'

tks

Answer 1

You can only do this if you added a trigger-maintained field that keeps track of the last change time.

There is no internal row timestamp in PostgreSQL, so in the absence of a trigger-maintained timestamp for the row, there's no way to find rows changed/added after a certain time.

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PostgreSQL does have internal information on the transaction ID that wrote a row, stored in the xmin hidden column. There's no record of what transaction ID committed when, though, until PostgreSQL 9.5 which keeps track of this if and only if the new track_commit_timestamps setting is turned on. Additionally, PostgreSQL eventually clears the creator transaction ID information from a tuple because it re-uses transaction IDs, so it only works for fairly recent transactions.

In other words: it's kind-of possible in a rough way, if you understand the innards of the database, but should really only be used for forensic and recovery purposes.