I have a table with two field in postgresql. One field is creation_time which is a timestamp with timezone and is filled with datetimes. Other field is foo which is filled by null values and I want to update this column by the epoch time of other column for each row.
How this is possible? I know that extract(epoch) can convert timestamp to epoch, but I don't know how to use it for my purpose.
This should work. foo should be of type bigint.
UPDATE table SET foo = EXTRACT(epoch FROM creation_time)
Related
I created a function that retrieves data from multiple table and insert the result into a new table. I am passing few dates in the where clause to filter the applicable information. The dates are in timestamptz format. The query takes roughly a min to process. However when I make the change in the where clause to pass the date from another table, the query lags a lot. i.e.
My initial argument that doesn't lag is
where timestamp = '2022-01-05 04:00:00+00'
The lag is when I change this where clause to pass this date from another table.
where timestamp = select date_time from table_Test
The date_time in table_test is defined as timestamptz and the value is '2022-01-05 04:00:00+00'.
Any idea why the query lags when I pass the date argument from another table?
Thanks,
I have data as following, But the column type is Varchar:
2019-09-28T23:59:59.52Z
I assume 52 here is milli seconds, If so..
I would like to convert it as following and change the column type to timestamp:
2019-09-28 23:59:59.52
Can someone let me know how I can convert in postgreSQL?
EDIT:
I can see data in table as (since the column type is varchar):
2019-09-28T23:59:59.52Z
Instead, I want data in the table to be shown as:
2019-09-28 23:59:59 ( and may be .52, if possible)
I need to change the column type to timestamp as well, I guess, Please help with that too.
Answer:
Tim has provided a solution, You can follow that.
But, In my case, It is prod env, So, I have just changed the type using:
ALTER TABLE my_table ALTER COLUMN my_column TYPE TIMESTAMP USING my_column::timestamp without time zone;
Thanks
Your timestamp string literal is already in a format which can be directly cast in Postgres:
SELECT '2019-09-28T23:59:59.52Z'::timestamp; -- 2019-09-28 23:59:59.52
As a test, let's add one day to make sure it's working:
SELECT '2019-09-28T23:59:59.52Z'::timestamp + interval '1 day';
-- 2019-09-29 23:59:59.52
If you want to actually add a new timestamp column using string data from another column, then try:
ALTER TABLE yourTable ADD COLUMN new_ts TIMESTAMP;
UPDATE yourTable SET new_ts = old_ts::timestamp;
ALTER TABLE yourTable DROP COLUMN old_ts;
ALTER TABLE yourTable RENAME COLUMN new_ts TO old_ts; -- optional
The last ALTER statement is optional if you want the new bona fide timestamp column to bear the same name as the old text timestamp column.
I have a column that requires a timestamp with time zone but I cannot use a built in pgSQL function nor can I modify the column to accept null dates. How can I insert a string date in the right format manually that represents no time?
There is no empty timestamp other than null, but you can use one of the special date/time values infinity or -infinity.
select 'infinity'::timestamp, '-infinity'::timestamp
timestamp | timestamp
-----------+-----------
infinity | -infinity
(1 row)
See Table 8.13. Special Date/Time Inputs.
I need storage 2 colums with date_time in my postgresql DB table.
date_time date_time_human
676484556463346 09.06.2017 9:38:00
date_time - like oracle timestamp( this date in seconds)
date_time_human - date in normal form
What type of field should be?
INSERT INTO tabl (date_time, date_time_human) VALUES(now(), now())
It seems to me that if you have the same value in these fields, then there is no sense in starting it twice.
Create one field of type timestamp. And in seconds you can output and record using functions.
Data Type Formatting Functions
Image I have a table containing the following two columns:
timestampwithouttimezone (of type TIMESTAMP WITHOUT TIME ZONE)
utcoffset (of type INTEGER)
I want to convert those two column to a single one of type TIMESTAMP WITH TIME ZONE. Can this be achieved using a ALTER TABLE ALTER COLUMN [column] SET DATE TYPE TIMESTAMP WITH TIME ZONE query and the additional USING clause?
Or do I need a separate UPDATE query that takes the offset and sets the timezone of the timestamps? If that's the case, what would that query be? I can't find any examples that show how to update the timezone using an integer.
You could do that like this, assuming the offset is in hours:
ALTER TABLE mytab
ALTER timestampwithouttimezone
TYPE timestamp with time zone
USING CAST (timestampwithouttimezone::text || ' '
|| to_char(utcoffset, 'S00FM')
AS timestamp with time zone),
DROP utcoffset;