What is a Unix Timestamp Simply put, the Unix timestamp is a way to track time as a running total of seconds. This count starts at the Unix Epoch on January 1st, 1970 at UTC. Therefore, the Unix timestamp is merely the number of seconds between a particular date and the Unix Epoch.
I have this timestamp value being return by a web service "2014-09-12T19:34:29Z" I know that it means timezone, but what exactly does it mean? And I am trying to mock this web service, so is the...
There is no true timestamp. Everybody choose own definition, so you should check that you are consistent. In any case, in one example you write date, and in one times, which can not really help us to find the problem. Not all definitions use UTC, some epoch will use a different start year. GPS includes leap seconds, Unix just doesn't update timestamp on leap seconds. "Unix epoch" is well ...
A TIMESTAMP column on the other hand takes the '2019-01-16 12:15:00' value you are setting into it and interprets it in the current session time zone to compute an internal representation relative to 1/1/1970 00:00:00 UTC. When the column is displayed, it will be converted back for display based on whatever the current session time zone is.
The differences are covered at the PostgreSQL documentation for date/time types. Yes, the treatment of TIME or TIMESTAMP differs between one WITH TIME ZONE or WITHOUT TIME ZONE. It doesn't affect how the values are stored; it affects how they are interpreted. The effects of time zones on these data types is covered specifically in the docs. The difference arises from what the system can ...
SELECT sensorID,timestamp,sensorField1,sensorField2 FROM sensorTable s1 WHERE timestamp = (SELECT MAX(timestamp) FROM sensorTable s2 WHERE s1.sensorID = s2.sensorID) ORDER BY sensorID, timestamp; Pretty self-explaining I think, but here's more info if you wish, as well as other examples. It's from the MySQL manual, but above query works with every RDBMS (implementing the sql'92 standard).
A frequently linked and heavily debated article. While I agree with the choice of a sortable format if it must be a string at all, a unix timestamp (which the article does not even acknowledge) has every one of the stated benefits and more. Until presentation, the issues of timezones and daylight savings (and political decisions) don't even exist.
