有没有办法减去 2 个时间戳并在 Redshift 中以 'hh:mm:ss' 格式获得结果

Question

I've been trying to get the duration between two timestamps using

select timestamp1-timestamp2 as time_s
from table_name

but I'm getting result as:

00:00:06.070627
00:00:33.415313
00:00:51.293319
00:02:00.146453
00:02:25.600623
00:06:37.811005
00:28:27.698517

I don't want the values after ' . '

I tried using

split_part(time_s, '.',1)

but it gave

6070627
33415313
51293319
120146453
145600623
397811005
1707698517

Can somebody please help?

Answer 1

The difference between two timestamps is an INTERVAL .

The basic problem that you are experiencing is that there is no standard way to display or return an Interval. For example:

• If you try your query in the web-based Redshift Query Editor, it will return NULL
• If you run it in your particular SQL Client, it is returning 00:00:06.070627
• If you run it in DbVisualizer, it is returning 0 years 0 mons 0 days 0 hours 0 mins 0.0 secs
• If you run it in DataGrip, it is returning Invalid character data was found

When you were attempting to extract a portion of the result to the left of the . , Redshift was confused because it does not see the output the way it is displayed in your SQL Client .

The best way to avoid your SQL Client from doing strange things to results is to convert the answer to TEXT :

SELECT (timestamp1 - timestamp2)::TEXT

This gives an answer like: 24 days 13:57:40.561373

You can then manipulate it like a string:

SELECT SPLIT_PART((timestamp1 - timestamp2)::TEXT, '.', 1)

This gives: 24 days 13:57:40

Bottom line: When things look strange in SQL results, cast the result to TEXT or VARCHAR to see what the data really looks like.