My database is Db2 for IBM i.
I have read-only access, so my query must use only basic SQL select commands.
==============================================================
Goal:
I want to select every record in the table until the sum of the amount column exceeds the predetermined limit.
Example:
I want to match every item down the table until the sum of matched values in the "price" column >= $9.00.
The desired result:
Is this possible?
You may use sum analytic function to calculate running total of price and then filter by its value:
with a as (
select
t.*,
sum(price) over(order by salesid asc) as price_rsum
from t
)
select *
from a
where price_rsum <= 9
SALESID | PRICE | PRICE_RSUM
------: | ----: | ---------:
1001 | 5 | 5
1002 | 3 | 8
1003 | 1 | 9
db<>fiddle here
Related
lets say I have a table which stores itemID, Date and total_shipped over a period of time:
ItemID | Date | Total_shipped
__________________________________
1 | 1/20/2000 | 2
2 | 1/20/2000 | 3
1 | 1/21/2000 | 5
2 | 1/21/2000 | 4
1 | 1/22/2000 | 1
2 | 1/22/2000 | 7
1 | 1/23/2000 | 5
2 | 1/23/2000 | 6
Now I want to aggregate based on several periods of time. For example, I Want to know how many of each item was shipped every two days and in total. So the desired output should look something like:
ItemID | Jan20-Jan21 | Jan22-Jan23 | Jan20-Jan23
_____________________________________________
1 | 7 | 6 | 13
2 | 7 | 13 | 20
How do I do that in the most efficient way
I know I can make three different subqueries but I think there should be a better way. My real data is large and there are several different time periods to be considered i. e. in my real problem I want the shipped items for current_week, last_week, two_weeks_ago, three_weeks_ago, last_month, two_months_ago, three_months_ago so I do not think writing 7 different subqueries would be a good idea.
Here is the general idea of what I can already run but is very expensive for the database
WITH
sq1 as (
SELECT ItemID, sum(Total_shipped) sum1
FROM table
WHERE Date BETWEEN '1/20/2000' and '1/21/2000'
GROUP BY ItemID),
sq2 as (
SELECT ItemID, sum(Total_Shipped) sum2
FROM table
WHERE Date BETWEEN '1/22/2000' and '1/23/2000'
GROUP BY ItemID),
sq3 as(
SELECT ItemID, sum(Total_Shipped) sum3
FROM Table
GROUP BY ItemID)
SELECT ItemID, sq1.sum1, sq2.sum2, sq3.sum3
FROM Table
JOIN sq1 on Table.ItemID = sq1.ItemID
JOIN sq2 on Table.ItemID = sq2.ItemID
JOIN sq3 on Table.ItemID = sq3.ItemID
I dont know why you have tagged this question with multiple database.
Anyway, you can use conditional aggregation as following in oracle:
select
item_id,
sum(case when "date" between date'2000-01-20' and date'2000-01-21' then total_shipped end) as "Jan20-Jan21",
sum(case when "date" between date'2000-01-22' and date'2000-01-23' then total_shipped end) as "Jan22-Jan23",
sum(case when "date" between date'2000-01-20' and date'2000-01-23' then total_shipped end) as "Jan20-Jan23"
from my_table
group by item_id
Cheers!!
Use FILTER:
select
item_id,
sum(total_shipped) filter (where date between '2000-01-20' and '2000-01-21') as "Jan20-Jan21",
sum(total_shipped) filter (where date between '2000-01-22' and '2000-01-23') as "Jan22-Jan23",
sum(total_shipped) filter (where date between '2000-01-20' and '2000-01-23') as "Jan20-Jan23"
from my_table
group by 1
item_id | Jan20-Jan21 | Jan22-Jan23 | Jan20-Jan23
---------+-------------+-------------+-------------
1 | 7 | 6 | 13
2 | 7 | 13 | 20
(2 rows)
Db<>fiddle.
One of my tables in my database contains rows with requisition numbers and other related info. I am trying to create a second table (populated with an INSERT INTO statement) that duplicates these rows and adds a series value based on the value in the QuantityOrdered column.
For example, the first table is shown below:
+-------------+----------+
| Requisition | Quantity |
+-------------+----------+
| 10001_01_AD | 4 |
+-------------+----------+
and I would like the output to be as follows:
+-------------+----------+----------+
| Requisition | Quantity | Series |
+-------------+----------+----------+
| 10001_01_AD | 4 | 1 |
| 10001_01_AD | 4 | 2 |
| 10001_01_AD | 4 | 3 |
| 10001_01_AD | 4 | 4 |
+-------------+----------+----------+
I've been attempting to use Row_Number() to sequence the values but it's numbering rows based on instances of Requisition values, not based on the Quantity value.
Non-recursive way:
SELECT *
FROM tab t
CROSS APPLY (SELECT n
FROM (SELECT ROW_NUMBER() OVER(ORDER BY 1/0) AS n
FROM master..spt_values s1) AS sub
WHERE sub.n <= t.Quantity) AS s2(Series);
db<>fiddle demo
You need recursive way :
with t as (
select Requisition, 1 as start, Quantity
from table
union all
select Requisition, start + 1, Quantity
from t
where start < Quantity
)
select Requisition, Quantity, start as Series
from t;
However, by default it has limited to only 100 Quantities, if you have a more then you need to specify the query hint by using option (maxrecursion 0).
A simple method uses recursive CTEs:
with cte as (
select requsition, quantity, 1 as series
from t
union all
select requsition, quantity, 1 + series
from t
where lev < quantity
)
select requsition, quantity, series
from cte;
With default setting, this works up to a quantity of 100. For larger quantities, you can add option (maxrecursion 0) to the query.
I have a table that has the following schema:
ID | FirstName | Surname | TransmissionID | CaptureDateTime
1 | Billy | Goat | ABCDEF | 2018-09-20 13:45:01.098
2 | Jonny | Cash | ABCDEF | 2018-09-20 13:45.01.108
3 | Sally | Sue | ABCDEF | 2018-09-20 13:45:01.298
4 | Jermaine | Cole | PQRSTU | 2018-09-20 13:45:01.398
5 | Mike | Smith | PQRSTU | 2018-09-20 13:45:01.498
There are well over 70,000 records and they store logs of transmissions to a web-service. What I'd like to know is how would I go about writing a script that would select the distinct TransmissionID values and also show the timespan between the earliest CaptureDateTime record and the latest record? Essentially I'd like to see what the rate of records the web-service is reading & writing.
Is it even possible to do so in a single SELECT statement or should I just create a stored procedure or report in code? I don't know where to start aside from SELECT DISTINCT TransmissionID for this sort of query.
Here's what I have so far (I'm stuck on the time calculation)
SELECT DISTINCT [TransmissionID],
COUNT(*) as 'Number of records'
FROM [log_table]
GROUP BY [TransmissionID]
HAVING COUNT(*) > 1
Not sure how to get the difference between the first and last record with the same TransmissionID I would like to get a result set like:
TransmissionID | TimeToCompletion | Number of records |
ABCDEF | 2.001 | 5000 |
Simply GROUP BY and use MIN / MAX function to find min/max date in each group and subtract them:
SELECT
TransmissionID,
COUNT(*),
DATEDIFF(second, MIN(CaptureDateTime), MAX(CaptureDateTime))
FROM yourdata
GROUP BY TransmissionID
HAVING COUNT(*) > 1
Use min and max to calculate timespan
SELECT [TransmissionID],
COUNT(*) as 'Number of records',datediff(s,min(CaptureDateTime),max(CaptureDateTime)) as timespan
FROM [log_table]
GROUP BY [TransmissionID]
HAVING COUNT(*) > 1
A method that returns the average time for all transmissionids, even those with only 1 record:
SELECT TransmissionID,
COUNT(*),
DATEDIFF(second, MIN(CaptureDateTime), MAX(CaptureDateTime)) * 1.0 / NULLIF(COUNT(*) - 1, 0)
FROM yourdata
GROUP BY TransmissionID;
Note that you may not actually want the maximum of the capture date for a given transmissionId. You might want the overall maximum in the table -- so you can consider the final period after the most recent record.
If so, this looks like:
SELECT TransmissionID,
COUNT(*),
DATEDIFF(second,
MIN(CaptureDateTime),
MAX(MAX(CaptureDateTime)) OVER ()
) * 1.0 / COUNT(*)
FROM yourdata
GROUP BY TransmissionID;
I have a table, my_table:
transaction_id | money | team
--------------------------------------------
1 | 10 | A
2 | 20 | B
3 | null | A
4 | 30 | A
5 | 16 | B
6 | 12 | B
When I group by team, I can compute max, min through query:
select team, max(money), min(money) from my_table group by team
However, I can't do avg and sum because there is null. i.e:
select team, avg(money), sum(money) from my_table group by team
would fail.
Is there a way to change the column type prior to computing the avg and sum? i.e. I want the output to be:
team | avg(money) | sum(money)
--------------------------------------
A | 20 | 40
B | 16 | 48
Thanks!
Per documentation provided by Cloudera your query should be working as-is. Both AVG Function and
SUM Function ignore null.
SELECT team, AVG(money), SUM(money)
FROM my_table
GROUP BY team
UPDATE: Per your comment, again I'm not familiar with Impala. Presumably standard SQL will work. Your error appears to be a datatype issue.
SELECT team, AVG(CAST(money AS INT)), SUM(CAST(money AS INT))
FROM my_table
GROUP BY team
Just divide the sum by the count:
SELECT team, SUM(money)/COUNT(money) AS AVG, SUM(money)
FROM team
GROUP BY team
Tested here: http://sqlfiddle.com/#!9/ba381/4
Lets says I have the following database table (date truncated for example only, two 'id_' preix columns join with other tables)...
+-----------+---------+------+--------------------+-------+
| id_table1 | id_tab2 | date | description | price |
+-----------+---------+------+--------------------+-------+
| 1 | 11 | 2014 | man-eating-waffles | 1.46 |
+-----------+---------+------+--------------------+-------+
| 2 | 22 | 2014 | Flying Shoes | 8.99 |
+-----------+---------+------+--------------------+-------+
| 3 | 44 | 2015 | Flying Shoes | 12.99 |
+-----------+---------+------+--------------------+-------+
...and I have a query like the following...
SELECT id, date, description FROM inventory ORDER BY date ASC;
How do I SELECT all the descriptions, but only once each while simultaneously only the latest year for that description? So I need the database query to return the first and last row from the sample data above; the second it not returned because the last row has a later date.
Postgres has something called distinct on. This is usually more efficient than using window functions. So, an alternative method would be:
SELECT distinct on (description) id, date, description
FROM inventory
ORDER BY description, date desc;
The row_number window function should do the trick:
SELECT id, date, description
FROM (SELECT id, date, description,
ROW_NUMBER() OVER (PARTITION BY description
ORDER BY date DESC) AS rn
FROM inventory) t
WHERE rn = 1
ORDER BY date ASC;