adding a column which calculates days until next event - sql

For a given Id, I have a series of START_DATE. Along with displaying other columns, I want to add a new column which finds the difference between the START_DATE for an Id(person), and his next START_DATE.
Basically, want to find the interval between his present START_DATE and his next START_DATE, along with displaying other columns.
For example, the data looks as follows
I tried doing this as follows :
SELECT t.Id,t.START_DATE,(select top 1 s.START_DATE from dbo.MyTable t INNER JOIN dbo.MyTable s ON(t.Id = s.Id and t.START_DATE > s.START_DATE) GROUP BY t.patient_Id,t.START_DATE)

I think this is what you need
SELECT t.Id,t.START_DATE,
DATEDIFF(day,(select min(s.START_DATE) from dbo.MyTable s
where t.Id = s.Id and t.START_DATE < s.START_DATE),
t.start_date) as DifferenceInDays
FROM dbo.MyTable t
This will give you (in days, you can change it if you want) the difference between each date and the next one

If your version of SQL Server supports it then you can do this with the LEAD windowed function like this:
SELECT
id,
start_date,
DATEDIFF(DAY, start_date, LEAD(start_date, 1) OVER (PARTITION BY id ORDER BY start_date)) AS days_until_next_start_date
FROM
dbo.My_Table

Related

Trying to display data that has more than a day gap between two dates on the same user?

I'm trying to create a query in Toad for Oracle that allows me to pull users who have had more than a one day gap between their previous and current supervisor(s) with a Supervisor Type of 'Registered Principal'.
For example, if the user has a Supervisor with an end date of 10/20/2019, I would expect to see a Supervisor assigned by 10/21/2019. If not then I would want those exceptions displayed since as of 10/22/2019, there is a one day gap. If date of '12/31/9999' is displayed then that means the supervisor is current.
SELECT DISTINCT a.AssocID, a.SupervisorAssocID, TRUNC(a.StartDate),
TRUNC(a.EndDate), a.SupervisorType
FROM TableName a
INNER JOIN (SELECT AssocID, StartDate, EndDate
FROM TableName
) b ON a.AssocID = b.AssocID
WHERE a.StartDate != TRUNC(b.StartDate)
AND TRUNC(b.EndDate) > a.StartDate
AND a.StartDate != TRUNC(b.EndDate)
AND a.SupervisorType = 'Registered Principal';
I expect to only see users who have had a gap of more than one day between Supervisors.
You can use LEAD analytic function to get the next start date:
SELECT *
FROM (
SELECT a.*,
LEAD( startdate ) OVER (
PARTITION BY AssocId
ORDER BY StartDate ASC
) AS next_startdate
FROM tablename a
-- WHERE SupervisorType = 'Registered Principal'
)
WHERE SupervisorType = 'Registered Principal'
AND TRUNC( enddate ) + INTERVAL '1' DAY < TRUNC( next_startdate )
Note: its unclear where you want to filter on SupervisorType; your query makes it seem like it should be the outer query but it could be the inner query if you only want to consider differences between Registered Principals and not any other type of supervisor.

postgres sql query to identify rows with same foreign key, but non consecutive dates

I have a table with a foreign_key_id column and a date column.
For each row that has the same foreign key, there is a different date, and if I order by foreign_key_id, date , 90% of the time all the dates are consecutive.
There are some edge cases though, where there are multiple entries with the same foreign_key that don't have consecutive dates.
Trying to come up with an easy way to identify all the foreign_key_id 's that don't have consecutive dates. Any ideas?
I was thinking of left joining on to a generated series, somehow partitioning by track id, but keep hitting a mental wall. My sql query editor keeps crashing, so that is adding some more unrelated frustration
EDIT:
I ended up doing an order by foreign_key_id, date , copying and pasting the result in excel, and then finding what I needed by doing this type of logic formula:
=IF( (B91 = B90), (F91 =(F90 + 1)) , 1 ) , where b is the foreign key column and F is the date column
but wondering if something similar could be done in sql. here's what I had when I gave up and went to excel:
select to_char(date_range.days, 'yyyy-mm-dd') as x
, data.*
from (
select generate_series('2019-04-30'::date,'2019-11-05'::date, '1 day')::date as days
) as date_range
left join(
select foreign_key_id, date
from table_a
order by foreign_key_id, date
) data on data.date = date_range.days
where foreign_key_id is null
You could do that, sure. No joins needed either. Use LAG(datecol) OVER(PARTITION BY foreignkeycol ORDER BY datecol) to get the date of the previous row for the same fk, diff it to the current date to show how many intervals (days? Minutes?) have passed since that date and then wrap it all in something that does WHERE thedifference <> 1 (Or however you define consecutive - if consecutive to you is "every 2 days" then it would be anything that doesn't have a difference of 2)
If you want both rows either side of the gap, use LEAD (same format as LAG) to get the next date and calc two diffs, then do WHERE difftoprev <> 1 or difftonext <>1 etc
It would look something like this (untested)
WITH cte AS (
SELECT foreignkeycol, datecol,
LAG(datecol) OVER(PARTITION BY foreignkeycol ORDER BY datecol) as prevdate,
LEAD(datecol) OVER(PARTITION BY foreignkeycol ORDER BY datecol) as nextdate
FROM table
)
SELECT *
FROM cte
WHERE
DATE_PART('day', datecol - prevdate) <> 1 OR
DATE_PART('day', nextdate - datecol) <> 1
I would use lead():
select t.*
from (select t.*,
lead(date) over (partition by foreign_key_id order by date) as next_date
from t
) t
where next_date <> date + interval '1 day';
This will provide each row where the next row does not have the expected date.

Same output in two different lateral joins

I'm working on a bit of PostgreSQL to grab the first 10 and last 10 invoices of every month between certain dates. I am having unexpected output in the lateral joins. Firstly the limit is not working, and each of the array_agg aggregates is returning hundreds of rows instead of limiting to 10. Secondly, the aggregates appear to be the same, even though one is ordered ASC and the other DESC.
How can I retrieve only the first 10 and last 10 invoices of each month group?
SELECT first.invoice_month,
array_agg(first.id) first_ten,
array_agg(last.id) last_ten
FROM public.invoice i
JOIN LATERAL (
SELECT id, to_char(invoice_date, 'Mon-yy') AS invoice_month
FROM public.invoice
WHERE id = i.id
ORDER BY invoice_date, id ASC
LIMIT 10
) first ON i.id = first.id
JOIN LATERAL (
SELECT id, to_char(invoice_date, 'Mon-yy') AS invoice_month
FROM public.invoice
WHERE id = i.id
ORDER BY invoice_date, id DESC
LIMIT 10
) last on i.id = last.id
WHERE i.invoice_date BETWEEN date '2017-10-01' AND date '2018-09-30'
GROUP BY first.invoice_month, last.invoice_month;
This can be done with a recursive query that will generate the interval of months for who we need to find the first and last 10 invoices.
WITH RECURSIVE all_months AS (
SELECT date_trunc('month','2018-01-01'::TIMESTAMP) as c_date, date_trunc('month', '2018-05-11'::TIMESTAMP) as end_date, to_char('2018-01-01'::timestamp, 'YYYY-MM') as current_month
UNION
SELECT c_date + interval '1 month' as c_date,
end_date,
to_char(c_date + INTERVAL '1 month', 'YYYY-MM') as current_month
FROM all_months
WHERE c_date + INTERVAL '1 month' <= end_date
),
invocies_with_month as (
SELECT *, to_char(invoice_date::TIMESTAMP, 'YYYY-MM') invoice_month FROM invoice
)
SELECT current_month, array_agg(first_10.id), 'FIRST 10' as type FROM all_months
JOIN LATERAL (
SELECT * FROM invocies_with_month
WHERE all_months.current_month = invoice_month AND invoice_date >= '2018-01-01' AND invoice_date <= '2018-05-11'
ORDER BY invoice_date ASC limit 10
) first_10 ON TRUE
GROUP BY current_month
UNION
SELECT current_month, array_agg(last_10.id), 'LAST 10' as type FROM all_months
JOIN LATERAL (
SELECT * FROM invocies_with_month
WHERE all_months.current_month = invoice_month AND invoice_date >= '2018-01-01' AND invoice_date <= '2018-05-11'
ORDER BY invoice_date DESC limit 10
) last_10 ON TRUE
GROUP BY current_month;
In the code above, '2018-01-01' and '2018-05-11' represent the dates between we want to find the invoices. Based on those dates, we generate the months (2018-01, 2018-02, 2018-03, 2018-04, 2018-05) that we need to find the invoices for.
We store this data in all_months.
After we get the months, we do a lateral join in order to join the invoices for every month. We need 2 lateral joins in order to get the first and last 10 invoices.
Finally, the result is represented as:
current_month - the month
array_agg - ids of all selected invoices for that month
type - type of the selected invoices ('first 10' or 'last 10').
So in the current implementation, you will have 2 rows for each month (if there is at least 1 invoice for that month). You can easily join that in one row if you need to.
LIMIT is working fine. It's your query that's broken. JOIN is just 100% the wrong tool here; it doesn't even do anything close to what you need. By joining up to 10 rows with up to another 10 rows, you get up to 100 rows back. There's also no reason to self join just to combine filters.
Consider instead window queries. In particular, we have the dense_rank function, which can number every row in the result set according to groups:
SELECT
invoice_month,
time_of_month,
ARRAY_AGG(id) invoice_ids
FROM (
SELECT
id,
invoice_month,
-- Categorize as end or beginning of month
CASE
WHEN month_rank <= 10 THEN 'beginning'
WHEN month_reverse_rank <= 10 THEN 'end'
ELSE 'bug' -- Should never happen. Just a fall back in case of a bug.
END AS time_of_month
FROM (
SELECT
id,
invoice_month,
dense_rank() OVER (PARTITION BY invoice_month ORDER BY invoice_date) month_rank,
dense_rank() OVER (PARTITION BY invoice_month ORDER BY invoice_date DESC) month_rank_reverse
FROM (
SELECT
id,
invoice_date,
to_char(invoice_date, 'Mon-yy') AS invoice_month
FROM public.invoice
WHERE invoice_date BETWEEN date '2017-10-01' AND date '2018-09-30'
) AS fiscal_year_invoices
) ranked_invoices
-- Get first and last 10
WHERE month_rank <= 10 OR month_reverse_rank <= 10
) first_and_last_by_month
GROUP BY
invoice_month,
time_of_month
Don't be intimidated by the length. This query is actually very straightforward; it just needed a few subqueries.
This is what it does logically:
Fetch the rows for the fiscal year in question
Assign a "rank" to the row within its month, both counting from the beginning and from the end
Filter out everything that doesn't rank in the 10 top for its month (counting from either direction)
Adds an indicator as to whether it was at the beginning or end of the month. (Note that if there's less than 20 rows in a month, it will categorize more of them as "beginning".)
Aggregate the IDs together
This is the tool set designed for the job you're trying to do. If really needed, you can adjust this approach slightly to get them into the same row, but you have to aggregate before joining the results together and then join on the month; you can't join and then aggregate.

Find the date after a gap in date range in sql

I have these date ranges that represent start and end dates of subscription. There are no overlaps in date ranges.
Start Date End Date
1/5/2015 - 1/14/2015
1/15/2015 - 1/20/2015
1/24/2015 - 1/28/2015
1/29/2015 - 2/3/2015
I want to identify delays of more than 1 day between any subscription ending and a new one starting. e.g. for the data above, i want the output: 1/24/2015 - 1/28/2015.
How can I do this using a sql query?
Edit : Also there can be multiple gaps in the subscription date ranges but I want the date range after the latest one.
You do this using a left join or not exists:
select t.*
from t
where not exists (select 1
from t t2
where t2.enddate = dateadd(day, -1, t.startdate)
);
Note that this will also give you the first record in the sequence . . . which, strictly speaking, matches the conditions. Here is one solution to that problem:
select t.*
from t cross join
(select min(startdate) as minsd from t) as x
where not exists (select 1
from t t2
where t2.enddate = dateadd(day, -1, t.startdate)
) and
t.startdate <> minsd;
You can also approach this with window functions:
select t.*
from (select t.*,
lag(enddate) over (order by startdate) as prev_enddate,
min(startdate) over () as min_startdate
from t
) t
where minstartdate <> startdate and
enddate <> dateadd(day, -1, startdate);
Also note that this logic assumes that the time periods do not overlap. If they do, a clearer problem statement is needed to understand what you are really looking for.
You can achieve this using window function LAG() that would get value from previous row in ordered set for later comparison in WHERE clause. Then, in WHERE you just apply your "gapping definition" and discard the first row.
SQL FIDDLE - Test it!
Sample data:
create table dates(start_date date, end_date date);
insert into dates values
('2015-01-05','2015-01-14'),
('2015-01-15','2015-01-20'),
('2015-01-24','2015-01-28'), -- gap
('2015-01-29','2015-02-03'),
('2015-02-04','2015-02-07'),
('2015-02-09','2015-02-11'); -- gap
Query
SELECT
start_date,
end_date
FROM (
SELECT
start_date,
end_date,
LAG(end_date, 1) OVER (ORDER BY start_date) AS prev_end_date
FROM dates
) foo
WHERE
start_date IS DISTINCT FROM ( prev_end_date + 1 ) -- compare current row start_date with previous row end_date + 1 day
AND prev_end_date IS NOT NULL -- discard first row, which has null value in LAG() calculation
I assume that there are no overlaps in your data and that there are unique values for each pair. If that's not the case, you need to clarify this.

How to count records for each day in a range (including days without records)

I'm trying to refine this question a little since I didn't really ask correctly last time. I am essentially doing this query:
Select count(orders)
From Orders_Table
Where Order_Open_Date<=To_Date('##/##/####','MM/DD/YYYY')
and Order_Close_Date>=To_Date('##/##/####','MM/DD/YYYY')
Where ##/##/#### is the same day. In essence this query is designed to find the number of 'open' orders on any given day. The only problem is I'm wanting to do this for each day of a year or more. I think if I knew how to define the ##/##/#### as a variable and then grouped the count by that variable then I could get this to work but I'm not sure how to do that-or there may be another way as well. I am currently using Oracle SQL on SQL developer. Thanks for any input.
You could use a "row generator" technique like this (edited for Hogan's comments):
Select RG.Day,
count(orders)
From Orders_Table,
(SELECT trunc(SYSDATE) - ROWNUM as Day
FROM (SELECT 1 dummy FROM dual)
CONNECT BY LEVEL <= 365
) RG
Where RG.Day <=To_Date('##/##/####','MM/DD/YYYY')
and RG.Day >=To_Date('##/##/####','MM/DD/YYYY')
and Order_Open_Date(+) <= RG.Day
and Order_Close_Date(+) >= RG.Day - 1
Group by RG.Day
Order by RG.Day
This should list each day of the previous year with the corresponding number of orders
Lets say you had a table datelist with a column adate
aDate
1/1/2012
1/2/2012
1/3/2012
Now you join that to your table
Select *
From Orders_Table
join datelist on Order_Open_Date<=adate and Order_Close_Date>=adate
This gives you a list of all the orders you care about, now you group by and count
Select aDate, count(*)
From Orders_Table
join datelist on Order_Open_Date<=adate and Order_Close_Date>=adate
group by adate
If you want to pass in a parameters then just generate the dates with a recursive cte
with datelist as
(
select #startdate as adate
UNION ALL
select adate + 1
from datelist
where (adate + 1) <= #lastdate
)
Select aDate, count(*)
From Orders_Table
join datelist on Order_Open_Date<=adate and Order_Close_Date>=adate
group by adate
NOTE: I don't have an Oracle DB to test on so I might have some syntax wrong for this platform, but you get the idea.
NOTE2: If you want all dates listed with 0 for those that have nothing use this as your select statement:
Select aDate, count(Order_Open_Date)
From Orders_Table
left join datelist on Order_Open_Date<=adate and Order_Close_Date>=adate
group by adate
If you want only one day you can query using TRUNC like this
select count(orders)
From orders_table
where trunc(order_open_date) = to_date('14/05/2012','dd/mm/yyyy')