Default value in select query for null values in postgres - postgresql

I have a table with sales Id, product code and amount. Some places product code is null. I want to show Missing instead of null. Below is my table.
salesId prodTypeCode amount
1 123 150
2 123 200
3 234 3000
4 234 400
5 234 500
6 123 200
7 111 40
8 111 500
9 1000
10 123 100
I want to display the total amount for every prodTypeCode with the option of If the prodTypeCode is null then Missing should be displayed.
select (CASE WHEN prodTypeCode IS NULL THEN
'Missing'
ELSE
prodTypeCode
END) as ProductCode, SUM(amount) From sales group by prodTypeCode
Above query giving error. Please suggest me to overcome this issue. I ahve created a SQLFIDDLE


The problem is a mismatch of datatypes; 'Missing' is text, but the product type code is numeric.
Cast the product type code to text so the two values are compatible:
select (CASE WHEN prodTypeCode IS NULL THEN
'Missing'
ELSE
prodTypeCode::varchar(40)
END) as ProductCode, SUM(amount) From sales group by prodTypeCode
See SQLFiddle.
Or, simpler:
select coalesce(prodTypeCode::varchar(40), 'Missing') ProductCode, SUM(amount)
from sales
group by prodTypeCode
See SQLFiddle.


Perhaps you have a type mismatch:
select coalesce(cast(prodTypeCode as varchar(255)), 'Missing') as ProductCode,
SUM(amount)
From sales s
group by prodTypeCode;
I prefer coalesce() to the case, simply because it is shorter.


I tried all 2 answers in my case and both did not work. I hope this snippet can help if both do not work for someone else:
SELECT
COALESCE(NULLIF(prodTypeCode,''), 'Missing') AS ProductCode,
SUM(amount)
From sales s
group by prodTypeCode;

Related

PostgreSQL SELECT COUNT returning a bunch of 1s

The following is my code that returns the correct number of rows of nameids that I am looking for (75). Then, when I do COUNT(DISTINCT nameid) at the top instead, it just returns 145 1s instead of the number of rows in my query (75). It just says
1
1
1
..
1
(145 rows)
What am I doing wrong?
SELECT
DISTINCT nameid
FROM
shop
WHERE
yearid >= 2000
GROUP BY
nameid,
yearid
HAVING
SUM(spend) > 98;

You should not use the same column in group by and in aggregated function in this way you obtain only 1 ( the distinct count of a value grouped bybthe same value is 1)
if you want count the DISTINCT nameid for each year with sum(spend) > 68 you should use
SELECT yearid, COUNT(DISTINCT nameid)
FROM shop
WHERE
yearid >= 2000
GROUP BY yearid
HAVING SUM(spend) > 98;

How to fix more than one columns returned error in PostgreSQL

I was trying to write a code to fetch records from a table and group by some columns but the subquery returns "more than one" error.
When I write the codes independently, I get a great awesome result but combining them is a problem.
select
year as Season,
cal_scheme as Scheme,
(case when cal_scheme='Mt.Elgon' then '1000'
when cal_scheme='West Nile' then '2000'
when cal_scheme='Rwenzori' then '1500' else '' end) as Target,
min(today::date) as startdatetime,
max(today::date)-min(today::date) as No_of_days,
(select count(id) as id from
kcl_internal_edit where new_farmer='' or new_farmer is null
group by year, cal_scheme)as growers
from kcl_internal_edit
group by year, cal_scheme
The expected result is to be as follows:
Season Scheme Target Startdatetime No_of_days growers
2019 Mt.Elgon 1000 28-10-2019 5 5
2019 West Nile 2000 29-05-2019 10 1
2018 Mt.Elgon 1500 29-08-2018 207 3

Your query should look like this:
select
year as Season,
cal_scheme as Scheme,
(case when cal_scheme='Mt.Elgon' then '1000'
when cal_scheme='West Nile' then '2000'
when cal_scheme='Rwenzori' then '1500' else '' end) as Target,
min(today::date) as startdatetime,
max(today::date)-min(today::date) as No_of_days,
count(id) FILTER (WHERE new_farmer='' or new_farmer is null) as growers
from kcl_internal_edit
group by year, cal_scheme;
There is no need for a subselect!

Calculate past 3 month average for every past 3rd month

I am using SQL Server 2014. I have a table like this
create table revenue (id varchar(2), trasdate date, revenue int);
insert into revenue(id, trasdate, revenue)
values ('aa', '2018/09/01', 1234.5),
('aa' , '2018/08/04', 450),
('aa', '2018/07/03',500),
('aa', '2018/06/04',600),
('ab', '2018/09/01', 1234.5),
('ab' , '2018/08/04', 450),
('ab', '2018/07/03',500),
('ab', '2018/06/04',600),
('ab', '2018/05/03', 200),
('ab', '2018/04/02', 150),
('ab', '2018/03/01', 350),
('ab', '2018/02/05', 700),
('aa', '2018/01/07', 400)
;
I am preparing a SQL query to create a SSRS report. I want to calculate a past 3 month average for current and every past 3rd month with result like below. As we are in month of September right now. The result should show something like this:
**id Period Revenue_3Mon**
aa March-May 233
aa June-Aug 516
ab March-May 233
ab June-Aug 516
Though I can figure out about the Period column. I was mainly focussing on getting the Revenue_3Mon. So I initially tried with the below query after some googling. But this query throws an error as incorrect syntax near 'rows' and if I remove rows from the query then it throws an error as Incorrect syntax near the keyword 'between'. And incorrect syntax near i.
select i.id,i.mon,
avg([i.mon_revenue]) over (partition by i.id, i.mon order by [i.id],
[i.mon] rows between 3 preceding and 1 preceding row) as revenue_3mon --
-- using 3 preceding and 1 preceding row you exclude the current row
from (select a.id, month(a.trasdate) as mon,
sum(a.revenue) as mon_revenue
from revenue a
group by a.id, month(a.trasdate)) i
group by i.id, i.mon
order by i.id,i.mon;
After few efforts, I gave up on this query and came up with new solution which was a bit close to my expectation (after lots of trial and errors).
Declare #count as int;
declare #max as int;
set #count = 4
declare #temp as table (id varchar(2), monthoftrasdate int, revenue int,
[3monavg] int);
SET #MAX = (SELECT distinct MAX(a.ROWNUM) FROM (SELECT id, month(trasdate)
as mon, SUM(revenue) TotalRevenue,
-- sum(revenue) as mon_revenue,
ROW_NUMBER() OVER(PARTITION BY ID ORDER BY MONTH(TRASDATE)) AS ROWNUM
FROM revenue
GROUP BY ID, MONTH(TRASDATE)
) A GROUP BY A.ID);
while (#count <= #max )
begin
WITH CTE AS (
SELECT id, month(trasdate) as mon, SUM(revenue) TotalRevenue,
-- sum(revenue) as mon_revenue,
ROW_NUMBER() OVER(PARTITION BY ID ORDER BY MONTH(TRASDATE)) AS
ROWNUM
FROM revenue
GROUP BY ID, MONTH(TRASDATE)
)
insert into #temp
SELECT A.ID,A.MON, a.TotalRevenue
,( SELECT avg(b.TotalRevenue) as avgrev
FROM CTE B
WHERE B.ROWNUM BETWEEN A.ROWNUM-3 AND A.ROWNUM-1
AND A.ID = B.ID --AND A.mon = B.mon
--and b.ROWNUM < a.ROWNUM
and (a.mon > 3 and a.ROWNUM > 3)
GROUP BY B.id
) AS REVENUE_3MON
FROM CTE A
set #count = #count + 1
end
select distinct a.* from #temp a
The reason I had to use 'distinct' is because the query was showing duplicate records for every id and every month. So far the result shows like below
id MonthofTrasdate Revenue 3MonAvg
aa 1 400 NULL
aa 2 700 NULL
aa 3 350 NULL
aa 4 150 483
aa 5 200 400
aa 6 600 233
aa 7 500 316
aa 8 450 433
aa 9 1234 516
ab 1 400 NULL
ab 2 700 NULL
ab 3 350 NULL
ab 4 150 483
ab 5 200 400
ab 6 600 233
ab 7 500 316
ab 8 450 433
ab 9 1234 516
This pulls out past 3 month average for every month. But i will just manipulate the rest on SSRS the way i want it.
As currently my table has no data for previous year. This works for me showing the appropriate result for next couple of months for now. But my concern is when I have to show my boss for next year Jan, Feb and March then it should be able to pull also for these months as well like Oct-Dec (Previous year), Nov-Jan and Dec - Feb. I am struggling to figure out the proper way to put this in my query.
Can you please help me out with this query? And also let me know what is wrong with my former query.

Problems with your first attempt:
You enclosed some of the aliases and column names in square brackets like [i.mon_revenue]. There is no need for square brackets, but if you want to use them, you have to break them up at the dot: [i].[mon_revenue].
In your window function expression, there is one row too many (in the end).
Window functions are applied at the very end (after the rest of the respective query), so you also have to include i.mon_revenue in your GROUP BY clause of the outer query.
Knowing that the inner query will produce one row per id and mon, there will never be preceding rows in an id-mon partition. Therefore, you must not partition by both, but only by id.
To simplify the query after resolving the issues: ordering by a partition column generally makes no sense, and since - as already mentioned - the inner query returns unique id-mon combinations, you don't have to group by these in the outer query. Looking at that query, we see that the outer query just directly selects and uses the values from the inner query, which makes a separation in two queries unneccessary. So, in fact, you wanted to perform the following query, which will produce the rolling 3-month average (I added the monthly TotalRevenue as well):
SELECT id, MONTH(trasdate) AS mon, SUM(revenue) AS TotalRevenue,
AVG(SUM(revenue)) OVER (PARTITION BY id ORDER BY MONTH(trasdate) ROWS BETWEEN 3 PRECEDING AND 1 PRECEDING) AS revenue_3mon
FROM revenue
GROUP BY id, MONTH(trasdate)
ORDER BY id, MONTH(trasdate);
Suggestions on your second attempt:
When calculating the #MAX value, you rely on the fact that each id has revenues for the same number of months. Are you sure?
The code inside the WHILE loop does not depend on #count, so it will add the same data into the #temp table multiple times, which is probably the reason why you thought you needed a DISTINCT. Therfore: No need for the variables, no need for a loop and a #temp, no need for DISTINCT.
The conditions A.mon > 3 and A.rownum > 3 are redundant with your current data. In general, I guess, you don't want to explicitly excluse the months from January to March, so A.mon > 3 should be removed. A.rownum > 3 could be removed, too, unless you really don't want to see a 3-month average when there are only 2 preceding months or less.
As the subquery for the average is restricted to only one id, there's no need for a GROUP BY.
Since the ROW_NUMBER function doesn't care about gaps in the months, I suggest to use a different numbering function, for example DATEDIFF(month, MAX(trasdate), GETDATE()) AS mnum. Of course, the comparison in the WHERE clause of the subquery then has to be changed to B.mnum BETWEEN A.mnum+1 AND A.mnum+3.
So, your second attempt can be reduced to this, which will produce the same result as the above, at least with your sample data, where no gaps in the months exist:
WITH CTE AS (
SELECT id, MONTH(trasdate) AS mon, SUM(revenue) AS TotalRevenue,
DATEDIFF(month, MAX(trasdate), GETDATE()) AS mnum
FROM revenue
GROUP BY id, MONTH(trasdate)
)
SELECT id, mon, TotalRevenue
, (SELECT AVG(B.TotalRevenue)
FROM CTE B
WHERE B.mnum BETWEEN A.mnum+1 AND A.mnum+3
AND A.id = B.id
) AS revenue_3mon
FROM CTE A
ORDER BY id, mnum DESC;
Now, guess what, an expression like my mnum using DATEDIFF increases by one every month as we move to the past, regardless of a change of years, so this might be useful for grouping as well, whether you want to (or can?) use Window functions or not:
With OVER()
SELECT id, MONTH(MIN(trasdate)) AS mon, YEAR(MIN(trasdate)) AS yr, SUM(revenue) AS TotalRevenue,
AVG(SUM(revenue)) OVER (PARTITION BY id ORDER BY MIN(trasdate) ROWS BETWEEN 3 PRECEDING AND 1 PRECEDING) AS revenue_3mon
FROM revenue
GROUP BY id, DATEDIFF(month, trasdate, GETDATE())
ORDER BY id, DATEDIFF(month, trasdate, GETDATE()) DESC;
Without OVER()
WITH CTE AS (
SELECT id, MIN(trasdate) AS min_dt, SUM(revenue) AS TotalRevenue,
DATEDIFF(month, trasdate, GETDATE()) AS mnum
FROM revenue
GROUP BY id, DATEDIFF(month, trasdate, GETDATE())
)
SELECT id, MONTH(min_dt) AS mon, YEAR(min_dt) AS yr, TotalRevenue
, (SELECT AVG(B.TotalRevenue)
FROM CTE B
WHERE B.mnum BETWEEN A.mnum+1 AND A.mnum+3
AND A.id = B.id
) AS revenue_3mon
FROM CTE A
ORDER BY id, mnum DESC;
Both queries allow for retrieving the minimum and maximum date for each period (including month and year).
If you instead wanted what you originally posted under The result should show something like this (just grouping by previous 3-months intervals), you just would have to group your original revenue table by id and (DATEDIFF(month, trasdate, GETDATE())-1)/3 (filtering WHERE DATEDIFF(month, trasdate, GETDATE()) > 0). If so, this kind of grouping and aggregation could, of course, be done also by the Report Server.

I think this should do what you want:
select r.*,
avg(r.mon_revenue) over (partition by r.id
order by r.mon_min
rows between 3 preceding and 1 preceding row
) as revenue_3mon
-- using 3 preceding and 1 preceding row you exclude the current row
from (select r.id, month(r.trasdate) as mon,
min(r.trasdate) as mon_min,
sum(r.revenue) as mon_revenue
from revenue r
group by r.id, year(r.trasdate), month(r.trasdate)
) 4
order by r.id, r.mon, r.mon_min;
Notes:
I fixed the code so it recognizes years as well as dates.
The expression [i.mon_revenue] is not a valid column reference (in your case). You have no column with the name "i.mon_revenue" (with the . in the name).
I changed the column alias to r to match the table.
I added a date column for each month to make it easier to express the ordering.
The outer group by is not necessary.

There are several syntax errors in your code. This should give you what you need. The inner query is the important bit but hopefully this will be enough to get you on your way.
I switch our the temp table for variable and changed the revenue column to not be INT as you have decimal values in there but other than that your original sample table is unchanged
DECLARE #revenue table (id varchar(2), trasdate date, revenue float)
insert into #revenue(id, trasdate, revenue)
values ('aa', '2018/09/01', 1234.5),
('aa' , '2018/08/04', 450),
('aa', '2018/07/03',500),
('aa', '2018/06/04',600),
('ab', '2018/09/01', 1234.5),
('ab' , '2018/08/04', 450),
('ab', '2018/07/03',500),
('ab', '2018/06/04',600),
('ab', '2018/05/03', 200),
('ab', '2018/04/02', 150),
('ab', '2018/03/01', 350),
('ab', '2018/02/05', 700),
('aa', '2018/01/07', 400)
SELECT
*
FROM
(
SELECT
*
, MONTH(trasdate) as MonthNumber
, AVG(revenue) OVER (PARTITION BY id
ORDER BY
id
, MONTH(trasdate) ROWS BETWEEN 3 PRECEDING AND 1 PRECEDING) as ThreeMonthAvg
FROM #revenue
) a
WHERE MONTH(GETDATE()) - MonthNumber IN (0, 3, 6, 9)
This gives the following results
aa 2018-06-04 600 6 400
aa 2018-09-01 1234.5 9 516.666666666667
ab 2018-03-01 350 3 700
ab 2018-06-04 600 6 233.333333333333
ab 2018-09-01 1234.5 9 516.666666666667

postgresql, convert column into header without rowid

I am trying to query a column into header and sum it.
I saw some example using crosstab but i can't figure out how to make it work without rowid
Is there other workaround to make this works?
My Table
currency| amount
RMB | 12
IDR | 30
RMB | 22
USD | 58
IDR | 30
Expected query
RMB_sum | IDR_sum | USD_sum
34 | 60 | 58

As you've stated you know in advance all the values in currency at the time of writing this query, you can simply use conditional aggregates. As you're on PostgreSQL 9.1 you can only accomplish this by mixing sum() with a case statement:
select
sum(case when currency = 'RMB' then amount else 0 end) as RMB_sum,
sum(case when currency = 'IDR' then amount else 0 end) as IDR_sum,
sum(case when currency = 'USD' then amount else 0 end) as USD_sum
from
__transactions
(Note the above uses implicit grouping - everything in my select statement is an aggregate function so there is no need to explicitly group the query)
If you were using PostgreSQL 9.4+ you could simplify the above with the filter directive:
select
sum(amount) filter(where currency = 'RMB') as RMB_sum,
sum(amount) filter(where currency = 'IDR') as IDR_sum,
sum(amount) filter(where currency = 'USD') as USD_sum
from
__transactions

PGSQL duplicate record in same column

i have a table and i want to know where duplicate records are present for same columns. These are my columns and i want to get record where group_id or week are different for same code and fweek and newcode
Id newcode fweek code group_id week
1 343001 2016-01 343 100 8
2 343002 2016-01 343 100 8
3 343001 2016-01 343 101 08
Required record is
Id newcode fweek code group_id week
3 343001 2016-01 343 101 08

To find the duplicate values i have joined the table with itself.
and we need to group the results with code,fweek and newcode to get more than one duplicate rows if they exist. i have used max() to get last inserted row.
you don't need to use is distinct from (it is same for inequality + NULL). if you don't want to compare NULL ones, use <> operator.
You find more information about here info
select r.*
from your_table r
where r.id in (select max(r.id)
from your_table r
join your_table r2 on r2.code = r.code and r2.fweek = r.fweek and r2.newcode = r.newcode
where
r2.group_id is distinct from r.group_id or
r2.week is distinct from r.week
group by r.code,
r.fweek,
r.newcode
having count(*) > 1)