Month Aggregation with 0 for NULL results - sum

Question

I have seen something similar but I can't get this to work:
SELECT
CNTRSINTDATA.DIM_CNTRS_DATE_ENTITY.CALENDAR_MONTH
, CNTRSINTDATA.FACT_QUICKBOOKS_TRANS_TSI.TSI_NOMINAL_CODE
, CNTRSINTDATA.DIM_CNTRS_TSI_COA.TSI_NOMINAL_ACC
, CNTRSINTDATA.DIM_CNTRS_DATE_ENTITY.CNTRS_FIN_YEAR
, SUM (CNTRSINTDATA.FACT_QUICKBOOKS_TRANS_TSI.QB_TRANS_AMOUNT) AS CNTRS_ACC_BUDGET
FROM
CNTRSINTDATA.FACT_QUICKBOOKS_TRANS_TSI
, CNTRSINTDATA.DIM_CNTRS_DATE_ENTITY
, CNTRSINTDATA.DIM_CNTRS_TSI_COA
WHERE
CNTRSINTDATA.FACT_QUICKBOOKS_TRANS_TSI.QB_TRANS_DATE = CNTRSINTDATA.DIM_CNTRS_DATE_ENTITY.CALENDAR_DATE
AND CNTRSINTDATA.DIM_CNTRS_DATE_ENTITY.CNTRS_FIN_YEAR LIKE '2017'
AND CNTRSINTDATA.FACT_QUICKBOOKS_TRANS_TSI.TSI_NOMINAL_CODE = CNTRSINTDATA.DIM_CNTRS_TSI_COA.TSI_NOMINAL_CODE
AND CNTRSINTDATA.FACT_QUICKBOOKS_TRANS_TSI.TSI_NOMINAL_CODE = '6598'
GROUP BY
CNTRSINTDATA.FACT_QUICKBOOKS_TRANS_TSI.TSI_NOMINAL_CODE
, CNTRSINTDATA.DIM_CNTRS_TSI_COA.TSI_NOMINAL_ACC
, CNTRSINTDATA.DIM_CNTRS_DATE_ENTITY.CALENDAR_MONTH
, CNTRSINTDATA.DIM_CNTRS_DATE_ENTITY.CNTRS_FIN_YEAR;`
The above query returns results for:
Feb-17 250
Jul-17 400
Jun-17 654
May-17 654
Oct-17 150
Nov-17 250
Aug-17 250
Sep-17
I need the rest of the months to also come back with zero's as there no transactions on the account that month.
Jan-17 0
Feb-17 250
Mar-17 0
Apr-17 0
Jul-17 400
Jun-17 654
May-17 654
Oct-17 150
Nov-17 250
Aug-17 250
Sep-17 0
Dec-17 0
There is a date table that has all the months as VARCHAR2 against date. Just cant get the right syntax. Can anyone help please?

Answer 1

Let's break that down and make it more manageable.
Firstly, translate that to SQL-92 join syntax and add some aliases
SELECT
dcde.CALENDAR_MONTH
, fqtt.TSI_NOMINAL_CODE
, dctc.TSI_NOMINAL_ACC
, dcde.CNTRS_FIN_YEAR
, SUM (fqtt.QB_TRANS_AMOUNT) AS CNTRS_ACC_BUDGET
FROM
CNTRSINTDATA.FACT_QUICKBOOKS_TRANS_TSI fqtt
INNER JOIN CNTRSINTDATA.DIM_CNTRS_DATE_ENTITY dcde
ON fqtt.QB_TRANS_DATE = dcde.CALENDAR_DATE
INNER JOIN CNTRSINTDATA.DIM_CNTRS_TSI_COA dctc
ON AND fqtt.TSI_NOMINAL_CODE = dctc.TSI_NOMINAL_CODE
WHERE
dcde.CNTRS_FIN_YEAR LIKE '2017'
AND
fqtt.TSI_NOMINAL_CODE = '6598'
GROUP BY
fqtt.TSI_NOMINAL_CODE
, dctc.TSI_NOMINAL_ACC
, dcde.CALENDAR_MONTH
, dcde.CNTRS_FIN_YEAR;
Next, you said that there exists a date record (presumably in CNTRSINTDATA.DIM_CNTRS_DATE_ENTITY), so swap that around
SELECT
dcde.CALENDAR_MONTH
, fqtt.TSI_NOMINAL_CODE
, dctc.TSI_NOMINAL_ACC
, dcde.CNTRS_FIN_YEAR
, SUM (fqtt.QB_TRANS_AMOUNT) AS CNTRS_ACC_BUDGET
FROM
CNTRSINTDATA.DIM_CNTRS_DATE_ENTITY dcde
INNER JOIN CNTRSINTDATA.FACT_QUICKBOOKS_TRANS_TSI fqtt
ON fqtt.QB_TRANS_DATE = dcde.CALENDAR_DATE
INNER JOIN CNTRSINTDATA.DIM_CNTRS_TSI_COA dctc
ON AND fqtt.TSI_NOMINAL_CODE = dctc.TSI_NOMINAL_CODE
WHERE
dcde.CNTRS_FIN_YEAR LIKE '2017'
AND
fqtt.TSI_NOMINAL_CODE = '6598'
GROUP BY
fqtt.TSI_NOMINAL_CODE
, dctc.TSI_NOMINAL_ACC
, dcde.CALENDAR_MONTH
, dcde.CNTRS_FIN_YEAR;
Finally, you don't actually want inner joins because that eliminates tuples where there is no match. In this case, you want a left join because you want to have the left value even if no value exists on the right. You also need to coalesce your sum expression to 0 because (for reasons I cannot fathom), the SQL standard defines the sum of a bunch records only containing null as null.
SELECT
dcde.CALENDAR_MONTH
, fqtt.TSI_NOMINAL_CODE
, dctc.TSI_NOMINAL_ACC
, dcde.CNTRS_FIN_YEAR
, COALESCE(SUM (fqtt.QB_TRANS_AMOUNT), 0) AS CNTRS_ACC_BUDGET
FROM
CNTRSINTDATA.DIM_CNTRS_DATE_ENTITY dcde
LEFT JOIN CNTRSINTDATA.FACT_QUICKBOOKS_TRANS_TSI fqtt
ON fqtt.QB_TRANS_DATE = dcde.CALENDAR_DATE
LEFT JOIN CNTRSINTDATA.DIM_CNTRS_TSI_COA dctc
ON AND fqtt.TSI_NOMINAL_CODE = dctc.TSI_NOMINAL_CODE
WHERE
dcde.CNTRS_FIN_YEAR LIKE '2017'
AND
fqtt.TSI_NOMINAL_CODE = '6598'
GROUP BY
fqtt.TSI_NOMINAL_CODE
, dctc.TSI_NOMINAL_ACC
, dcde.CALENDAR_MONTH
, dcde.CNTRS_FIN_YEAR;
Give that a try and see if it is what you want

Answer 2

#Adam G,
Thank you for your suggestion. I actually got an idea from your commentry and instead created a select statement to get all the months I needed first. After that I joined to a select statement picking up the transactions where months matched and it worked. See below (come table names have changed)
SELECT DISTINCT
CNTRS_DATE_ENTITY.CALENDAR_MONTH
, CNTRS_DATE_ENTITY.CNTRS_FIN_MONTH_POS
, COALESCE (TRANS_DATA.TRANS_AMOUNT,0) AS TRANS_AMOUNT
FROM
CNTRSINTDATA.DIM_CNTRS_DATE_ENTITY CNTRS_DATE_ENTITY
LEFT JOIN
(
SELECT
QBS_TRANS_TSI.QB_NOMINAL_CODE
, TO_CHAR(QBS_TRANS_TSI.QB_TRANS_DATE, 'Mon-YY') AS TRANS_MONTH
, COALESCE (SUM(QBS_TRANS_TSI.QB_TRANS_AMOUNT),0) AS TRANS _AMOUNT
FROM
CNTRSINTDATA.FACT_QBS_TRANS_TSI QBS_TRANS_TSI
WHERE
QBS_TRANS_TSI.TSI_NOMINAL_CODE = '6598'
GROUP BY
QBS_TRANS_TSI.QB_NOMINAL_CODE
, TO_CHAR(QBS_TRANS_TSI.QB_TRANS_DATE, 'Mon-YY')
) TRANS_DATA
ON TRANS_DATA.TRANS_MONTH = CNTRS_DATE_ENTITY.CALENDAR_MONTH
WHERE
CNTRS_DATE_ENTITY.CNTRS_FIN_YEAR LIKE '2017'
ORDER BY
CNTRS_DATE_ENTITY.CNTRS_FIN_MONTH_POS
However the results have all the months but have blanks in the entity columns where the sum is zero. Any ideas on a remedy for this?

Answer 3

Here is one possible solution:
Generate fake empty transactions for the target period
for example using CTE:
declare #StartDate datetime = '20170101'
declare #EndDate datetime = '20171231'
;
with dt as
(
select #StartDate As 'thedate'
union all
select dateadd(month, 1, thedate) from dt where thedate < dateadd(month, -1, #EndDate)
)
select
dt.thedate 'row date',
datename(month,dt.thedate) 'Month',
YEAR(dt.thedate) 'Year',
0 'Amount '
from dt
Now you can add them to the transaction table (like union all) or you can do a left join with filtering on the result of your query.
I hope it helps! 🙂