Hi I want to implement the following between clause in sql db2:
between start_date - 1 days and end_date
where start_date and end_date are standard dates, and I want to search between the day before the start_date up to the end_date. I however get the following error:
An expression with a datetime value or a labeled duration is not valid
however if I try:
between start_date and end_date + 1 days
there are no complaints. how do I get the first clause to work?
Thanks
Have you tried using parentheses?
Related
I am facing an issue extracting the month and year from the data (in Character varying type) >> InvoiceDate in SQL Postgres. I have seen the solution is relatively easy with MySQL function: DATEFROMPARTS as per the below Code which is not available in SQLpostgres. How can I get the same result DATA_PART function in Postgres SQL, but simultaneously I need to change the data type of the column "InvoiceDate" to the date
Select
CustomerID,
min(InvoiceDate) first_purchase_date,
DATEFROMPARTS(year(min(InvoiceDate)), month(min(InvoiceDate)), 1) Cohort_Date
into #cohort
from #online_retail_main
group by CustomerID
The output:
Customer ID| first_purchase_date |Cohort_Date|
-----------+-------------------------+-----------+
12345 | 2010-12-20 15:47:00:00 | 2010-12-01|
I am trying to make a date consits of Year and Month , while the day to be set as 1 for all
Assuming a valid Postgres timestamp:
select date_trunc('month', '2010-12-20 15:47:00.00'::timestamp)::date;
date_trunc
------------
12/01/2010
--or ISO format
set datestyle = 'ISO,MDY';
select date_trunc('month', '2010-12-20 15:47:00.00'::timestamp)::date;
date_trunc
------------
2010-12-01
Uses date_trunc to truncate the timestamp to a month which means the first of the month. Then cast(::date) to a date type. The DateStyle just deals with how the value is presented to the user. The value is not stored formatted.
To do something similar to what you did in MySQL:
select make_date(extract(year from '2010-12-20 15:47:00.00'::timestamp)::integer, extract(month from '2010-12-20 15:47:00.00'::timestamp)::integer, 1);
This uses make_date from here Date/time functions and extract to build a date.
I have problem select data between two dates if the only start_date is available.
The example I want to see is what discount_nr was active between 2020-07-01 and 2020-07-15 or only one day 2020-07-14. I tried different solutions, date range, generate series, and so on, but was still not able to get it to work.
Table only have start dates, no end dates
Example:
discount_nr, start_date
1, 2020-06-30
2, 2020-07-03
3, 2020-07-10
4, 2020-07-15
You can get the end dates by looking at the start date of the next row. This is done with lead. lead(start_date) over(order by start_date asc) will get you the start_date of the next row. If we take 1 day from that we'll get the inclusive end date.
Rather than separate start/end columns, a single daterange column is easier to work with. You can use that as a CTE or create a view.
create view discount_durations as
select
id,
daterange(
start_date,
lead(start_date) over(order by start_date asc)
) as duration
from discounts
Now querying it is easy using range operators. #> to check if the range contains a date.
select *
from discount_durations
where duration #> '2020-07-14'::date
And use && to see if they have any overlap.
select *
from discount_durations
where duration && daterange('2020-07-01', '2020-07-15');
Demonstration
I have a customer_visit table, my requirement is to get the records of previous month starting from 3rd date to current month 2nd date and which contains flag 'Y'. How can I achieve this in Postgres. Following is the sample of my table. Any help is appreciated.
Use make_date() function from postgres to construct the date and query on it.
select * from customer_visit
where created_time > make_date(2018, date_part('month', now())::int - 1, 03)
and created_time <= make_date(2018, date_part('month', now())::int, 02)
and flag = 'Y';
You can use date_part('year', timestamp) to extract year also from current date.
I would like to subtract one month from a date column in Amazon Redshift (a fork of PostgreSQL 8.0.2).
So for each date column in a table, it will add another column date_minus_a_month.
I tried this code
Select date,date::date -interval '1 month'
from table
and received an error:
Interval values with month or year parts are not supported.
Does anyone have a solution for this?
You can use datesub, although I just use dateadd for everything and use negative numbers.
eg
SELECT getdate() as right_now, dateadd(month, -1, getdate()) as last_month
Docs: https://docs.aws.amazon.com/redshift/latest/dg/r_DATEADD_function.html
Below is my query in postgres
select dns_time,update_time from dns_lookup where update_time=current_date;
Here update_time is of type timestamp with time zone.
I have tried this one also.
select dns_time,update_time from dns_lookup where update_time like current_date;
Then also getting no results.
I have records with current_date values.But it is not showing me any records.How to compare timestamp with time zone value with current_date.please help me
Thank you.
First: LIKE on a date or timestamp column does not make any sense.
A timestamp contains a time part so a comparison with a plain date won't work. You need to remove the time from the timestamp by casting it to a date:
where cast(update_time as date) = current_date;
Note that this will void the usage of an index on update_time. If that is a problem you can create a function based index on that expression.
You might be trying to compare a timestamp field with the Date field.
Try casting timestamp to Date
select dns_time,update_time from dns_lookup where update_time::Date=current_date;
Hope this helps.