Lets say I have a table which storing HOURS and MINUTES in two different column.
For example:
HOURS|MINUTES
------------------
1|11
2|22
3|33
How can I merge the hours and minutes in my table into current timestamp
My concept are as below
SELECT TRUNC(CURRENT TIMESTAMP) + HOURS + MINUTES FROM MYTABLE;
try this one
select current timestamp + HOURS hour + MINUTES minute
from sysibm.sysdummy1
After several hours of trying i find out that i need to further enhance my table design, instead of storing minute and hours in different column, is better that i store in in single column. The sample value can be '18:36:00'
then use the following query to convert it
(SELECT CAST(? AS TIMESTAMP) + HOUR(TIME(END_TIMESTAMP)) HOURS + MINUTE(TIME(END_TIMESTAMP)) MINUTES FROM MY_TABLE
Related
I want to create a query in Oracle SQL that will grab records from a given time interval, during certain hours of the day, e.g. records between 10am to noon, in the past 10 days. I tried this, but it does not work:
select * from my_table where timestamp between
to_timestamp('2020-12-30','YYYY-MM-DD')
and
to_timestamp('2021-01-08','YYYY-MM-DD') and
timestamp between
to_timestamp('10:00:00','HH24:MI:SS')
and
to_timestamp('12:00:00','HH24:MI:SS')
where timestamp is of type TIMESTAMP. I have also thought of using a join, but I am struggling to find a way to filter on time of day.
Is there a way to filter using only the time, not the date, or a way to filter on time for every day in the interval?
select *
from my_table
where timestamp between to_timestamp('2020-12-30','YYYY-MM-DD')
and to_timestamp('2021-01-08','YYYY-MM-DD')
and timestamp - trunc(timestamp) between interval '10' hour
and interval '12' hour
If you don't need to include exactly noon (including no fractional seconds), you could also do
select *
from my_table
where timestamp between to_timestamp('2020-12-30','YYYY-MM-DD')
and to_timestamp('2021-01-08','YYYY-MM-DD')
and extract( hour from timestamp ) between 10 and 11
As an aside, I'd hope that your actual column name isn't timestamp. It's legal as a column name but it is a reserved word so you're generally much better off using a different name.
I'm trying to retrieve data for a specific date with query:
Select * from table_1 where activity_date = to_date('13-09-2017','DD-MM-YYYY');
But I'm not getting any result.
But when I query below:
Select * from table_1 where activity_date >= to_date('13-09-2017','DD-MM-YYYY');
I'm getting the data for days greater than equal to 13-09-2017.
Any help?
It seems the data type of your column is Date Time and hence when you are querying with just date (13-09-2017), it searching for date as well as time (13-09-2017 00:00:00). Seems there are no record in your database with this exact date time stamp and hence no results are being returned. Below query will work in your case:
SELECT *
FROM table_1
WHERE activity_date >= to_date('13-09-2017','DD-MM-YYYY')
AND activity_date < to_date('14-09-2017','DD-MM-YYYY');
When you compare dates remember that you usually compare some kind of a timestamp. A timestamp usually also has hours, minutes, seconds etc. So in your database you probably have a whole timestamp like '13-09-2017' + specific hour, minutes and so on, whilst to_date explicitly only formats your DD MM and YYYY causing the hour, minutes and seconds to be equal to 0. The query is probably not returning any records as you probably don't have a date with the exact time equal to 00:00:00.
That's also why a comparison like >= will return results. Because your '13-09-2017' database entries are all greater than '13-09-2017' (with hour equal to 00:00:00) because they all have some hours, minutes and seconds to them, for e.g 13-09-2017 04:02:45 which is greater than 13-09-2017 00:00:00).
How to solve this? Well for example:
SELECT *
FROM table_1
WHERE activity_date >= to_date('13-09-2017','DD-MM-YYYY')
AND activity_date < to_date('14-09-2017','DD-MM-YYYY')
I have a table with 17,000 records that is ordered by time spaced in 15 minute intervals. The time values loop back onto themselves every 24 hours, so for example, I could have 100 records that are all at 1 AM, just on different days. I want to create a 'average day' by taking those 100 records at 1 am and finding the average of them for the averaged 1 am.
I don't know how to format the table to make it show up nicely here.
I'm assuming you want to calculate the average value per time interval regardless of the day in a query. You could use this SQL to group your table by Time interval only (assuming that it's separate from the date field), and average whichever fields you want to average. Do not select or group by the date field, just select and group by the time field.
SELECT TimeField
, AVG([Field1ToAverage])
, AVG([Field2ToAverage])
FROM MyTable
GROUP BY TimeField;
If the date and time fields are stored together in the same column, you will have to extract the time only:
SELECT TimeValue([DateTimeField])
, AVG([Field1ToAverage])
, AVG([Field2ToAverage])
FROM MyTable
GROUP BY TimeValue([DateTimeField]);
I am using Postgres v9.2.6.
Have a system with lots of devices that take measurements. These measurements are stored in
table with three fields.
device_id
measurement (Indexed)
time (Indexed)
There could be 10 Million measurements in a single year. Most of the time the user is only interested in 100 min max pairs within equal interval for a certain period, for example in last 24 hours or in last 53 weeks. To get these 100 mins and maxs the period is divided into 100 equal intervals. From each interval min and max is extracted. Would you recommend the most efficient approach to query the data? So far I have tried the following query:
WITH periods AS (
SELECT time.start AS st, time.start + (interval '1 year' / 100) AS en FROM generate_series(now() - interval '1 year', now(), interval '1 year' / 100) AS time(start)
)
SELECT * FROM sample_data
JOIN periods
ON created_at BETWEEN periods.st AND periods.en AND
customer_id = 23
WHERE
sample_data.id = (SELECT id FROM sample_data WHERE created_at BETWEEN periods.st AND periods.en ORDER BY sample ASC LIMIT 1)
This test approach took over a minute for 1 million points on MacBook Pro.
Thanks...
Sorry about that. It was actually my question and looks like the author of this post caught cold so I ca not ask him to edit it. I've posted "more good" question here - Slow PostgreSQL Query for Mins and Maxs within equal intervals in a time period. Could you please close this question?
Using DB2 SQL
I would like to query for records since 2:00 yesterday. I want a dynamic expression that frees me from having to manually enter the current date prior to running the query. The created_datetime attribute is of timestamp dataype.
For example:
select record_key, other_stuff
from table
where created_datetime > "2 o'clock PM yesterday"
Is this kind of dynamic timestamp comparison even possible? Eventually, I'd like to be able to do a window of time, which gets complicated!
select count(1)
from table
where created_datetime between "2 o'clock PM yesterday" and "2 o'clock PM today"
I am familiar with current date, but I am trying to conceptualize how I would leverage that. The following gets me close, but it includes everything 24 hours prior to whenever the query is run.
select count(1)
from table
where created_datetime between (currentdate - 1 day) and (currentdate # 2 o'clock PM)
I know this is some pretty basic territory, and I feel guilty posting this question, but my research has not turned up anything for me so far. I appreciate every ounce of time spent on my behalf.
Try these
select record_key, other_stuff
from table
where created_datetime > CURRENT DATE - 10 HOURS
select count(1)
from table
where created_datetime between (CURRENT DATE - 10 HOURS) and (CURRENT DATE + 14 HOURS)
select count(1)
from table
where created_datetime between (CURRENT DATE - 1 DAYS) and (CURRENT DATE + 14 HOURS)
From the IBM Dev Works Library : DB2 Basics: Fun with Dates and Times
There are heaps of samples there.
E.g.
You can also perform date and time calculations using, for lack of a
better term, English:
current date + 1 YEAR
current date + 3 YEARS + 2 MONTHS + 15 DAYS
current time + 5 HOURS - 3 MINUTES + 10 SECONDS
Try this with this Timestamp option in you where clause.
Below sample to query for between last 24 hours.
select
timestamp(CURRENT date - 1 days,(CURRENT time - 24 hours)),
timestamp(CURRENT date,CURRENT time )
FROM
sysibm.sysdummy1;