How to extract hour from query in postgres - sql

I have timestamp in my table and i want to extract only hour from it. I search and find a extract function but unable to use as a query. Do i need to convert first timestamp in varchar and then extract hour from it?
Here is my query:
select extract(hour from timestamp '2001-02-16 20:38:40') // example
actual query:
select extract(hour from timestamp observationtime) from smartvakt_device_report

The following should work
select extract(hour from observationtime) from smartvakt_device_report

SELECT to_char(now(), 'HH24:MI:SS') hour_minute_second

The word timezone is redundant (read: wrong). You just need to give the column's name. E.g.:
db=> select extract(hour from observationtime) from smartvakt_device_report;
date_part
-----------
19
(1 row)

EXTRACT does not work with Grafana but date_part does.
The solution for me was:
SELECT date_part('hour', observationtime::TIMESTAMP) FROM smartvakt_device_report;
Reference: https://www.postgresql.org/docs/current/functions-datetime.html#FUNCTIONS-DATETIME-EXTRACT

Related

How can I do to get the hour from a date column with Postgres? [duplicate]

I have timestamp in my table and i want to extract only hour from it. I search and find a extract function but unable to use as a query. Do i need to convert first timestamp in varchar and then extract hour from it?
Here is my query:
select extract(hour from timestamp '2001-02-16 20:38:40') // example
actual query:
select extract(hour from timestamp observationtime) from smartvakt_device_report
The following should work
select extract(hour from observationtime) from smartvakt_device_report
SELECT to_char(now(), 'HH24:MI:SS') hour_minute_second
The word timezone is redundant (read: wrong). You just need to give the column's name. E.g.:
db=> select extract(hour from observationtime) from smartvakt_device_report;
date_part
-----------
19
(1 row)
EXTRACT does not work with Grafana but date_part does.
The solution for me was:
SELECT date_part('hour', observationtime::TIMESTAMP) FROM smartvakt_device_report;
Reference: https://www.postgresql.org/docs/current/functions-datetime.html#FUNCTIONS-DATETIME-EXTRACT

SQL extracting hour and minute from date into a single column

I have a column in the format YYYY-MM-DDBHH:MI:SS and I wish to extract just the hour and minutes from this into a column. Currently on the code they are using
Extract(HOUR From table) AS HR
, Extract(MINUTE From table) AS MN
but this outputs them into 2 columns. I'm new to SQL so is there an easier way to extract hour and minutes into one column in the format HH:MI.
Thanks
Using Teradata, simply concatenate the output from each of the functions to give the answer:
Extract(HOUR From table) || ':' || Extract(MINUTE From table) AS OUTPUT
Don't know about teradata but something like this.
SELECT CONCAT(Extract(HOUR From table),Extract(MINUTE From table)) as HRandMI
If you got a Timestamp the easiest way to get a HH:MI string is:
to_char(mycol, 'HH24:MI')

How can I extract just the hour of a timestamp using standardSQL

How can I extract just the hour of a timestamp using standardSQL.
I've tried everything and no function works. The problem is that I have to extract the time from a column and this column is in the following format:2018-07-09T02:40:23.652Z
If I just put the date, it works, but if I put the column it gives the error below:
Syntax error: Expected ")" but got identifier "searchIntention" at [4:32]
Follow the query below:
#standardSQL
select TOTAL, dia, hora FROM
(SELECT cast(replace(replace(searchIntention.createdDate,'T',' '),'Z','')as
DateTime) AS DIA,
FORMAT_DATETIME("%k", DATETIME searchIntention.createdDate) as HORA,
count(searchintention.id) as Total
from `searchs.searchs2016626`
GROUP BY DIA)
Please, help me. :(
How can I extract just the hour of a timestamp using standardSQL?
Below is for BigQuery Standard SQL
You can use EXTRACT(HOUR FROM yourTimeStampColumn)
for example:
SELECT EXTRACT(HOUR FROM CURRENT_TIMESTAMP())
or
SELECT EXTRACT(HOUR FROM TIMESTAMP '2018-07-09T02:40:23.652Z')
or
SELECT EXTRACT(HOUR FROM TIMESTAMP('2018-07-09T02:40:23.652Z'))
In BigQuery Standard SQL, you can use the EXTRACT timestamp function in order to return an INT64 value corresponding to the part of the timestamp that you want to retrieve, like.
The available parts includes a full list that you can check in the documentation page linked, but in your use case you can directly refer to the HOUR operator in order to retrieve the INT64 representation of the hour value in a field of TIMESTAMP type.
#standardSQL
# Create a table
WITH table AS (
SELECT TIMESTAMP("2018-07-09T02:40:23.652Z") time
)
# Extract values from a Timestamp expression
SELECT
EXTRACT(DAY FROM time) as day,
EXTRACT(MONTH FROM time) as month,
EXTRACT(YEAR FROM time) as year,
EXTRACT(HOUR FROM time) AS hour,
EXTRACT(MINUTE FROM time) as minute,
EXTRACT(SECOND from time) as second
FROM
table

Timestamp to date convertion in oracle sql [duplicate]

How can we convert timestamp to date?
The table has a field, start_ts which is of the timestamp format:
'05/13/2016 4:58:11.123456 PM'
I need to query the table and find the maximum and min timestamp in the table but I'm not able to.
Select max(start_ts)
from db
where cast(start_ts as date) = '13-may-2016'
But the query is not returning any values.
Please help me in finding the max timestamp for a date.
CAST(timestamp_expression AS DATE)
For example, The query is : SELECT CAST(SYSTIMESTAMP AS DATE) FROM dual;
Try using TRUNC and TO_DATE instead
WHERE
TRUNC(start_ts) = TO_DATE('2016-05-13', 'YYYY-MM-DD')
Alternatively, you can use >= and < instead to avoid use of function in the start_ts column:
WHERE
start_ts >= TO_DATE('2016-05-13', 'YYYY-MM-DD')
AND start_ts < TO_DATE('2016-05-14', 'YYYY-MM-DD')
Format like this while selecting:
to_char(systimestamp, 'DD-MON-YYYY')
Eg:
select to_char(systimestamp, 'DD-MON-YYYY') from dual;
If the datatype is timestamp then the visible format is irrelevant.
You should avoid converting the data to date or use of to_char. Instead compare the timestamp data to timestamp values using TO_TIMESTAMP()
WHERE start_ts >= TO_TIMESTAMP('2016-05-13', 'YYYY-MM-DD')
AND start_ts < TO_TIMESTAMP('2016-05-14', 'YYYY-MM-DD')
You can try the simple one
select to_date('2020-07-08T15:30:42Z','yyyy-mm-dd"T"hh24:mi:ss"Z"') from dual;
You can use:
select to_date(to_char(date_field,'dd/mm/yyyy')) from table
I'd go with the following:
Select max(start_ts)
from db
where trunc(start_ts) = date'13-may-2016'
If you have milliseconds in the date string, you can use the following.
select TO_TIMESTAMP(SUBSTR('2020-09-10T09:37:28.378-07:00',1,23), 'YYYY-MM-DD"T"HH24:MI:SS:FF3')From Dual;
And then convert it to Date with:
select trunc(TO_TIMESTAMP(SUBSTR('2020-09-10T09:37:28.378-07:00',1,23), 'YYYY-MM-DD"T"HH24:MI:SS:FF3')) From Dual;
It worked for me, hope it will help you as well.
This may not be the correct way to do it. But I have solved the problem using substring function.
Select max(start_ts), min(start_ts)from db where SUBSTR(start_ts, 0,9) ='13-may-2016'
using this I was able to retrieve the max and min timestamp.

How to get the date and time from timestamp in PostgreSQL select query?

How to get the date and time only up to minutes, not seconds, from timestamp in PostgreSQL. I need date as well as time.
For example:
2000-12-16 12:21:13-05
From this I need
2000-12-16 12:21 (no seconds and milliseconds only date and time in hours and minutes)
From a timestamp with time zone field, say update_time, how do I get date as well as time like above using PostgreSQL select query.
Please help me.
There are plenty of date-time functions available with postgresql:
See the list here
http://www.postgresql.org/docs/9.1/static/functions-datetime.html
e.g.
SELECT EXTRACT(DAY FROM TIMESTAMP '2001-02-16 20:38:40');
Result: 16
For formatting you can use these:
http://www.postgresql.org/docs/9.1/static/functions-formatting.html
e.g.
select to_char(current_timestamp, 'YYYY-MM-DD HH24:MI') ...
To get the date from a timestamp (or timestamptz) a simple cast is fastest:
SELECT now()::date
You get the date according to your local time zone either way.
If you want text in a certain format, go with to_char() like #davek provided.
If you want to truncate (round down) the value of a timestamp to a unit of time, use date_trunc():
SELECT date_trunc('minute', now());
This should be enough:
select now()::date, now()::time
, pg_typeof(now()), pg_typeof(now()::date), pg_typeof(now()::time)