Joining multiple date fields to calendar table - sql-server

Question

I have a table, let's call it Records, where the relevant data is organized as such:
| Employee | SubmissionDate | FirstReviewDate | SecondReviewDate |
Anne 2017-10-02 2017-10-03 2017-10-10
Bernard 2017-10-03 2017-10-05 2017-10-10
Charlene 2017-10-06 2017-10-09 2017-10-09
Danielle 2017-10-02 2017-10-03 2017-10-09
Anne 2017-10-03 2017-10-03 2017-10-09
Every time an employee makes a submission, a new entry is added with a SubmissionDate. The record is later edited to include then the first and second reviews take place.
I also have a calendar table called Calendar with a field called TheDate which has dates for every day this year. What I would like to do is associate SubmissionDate, FirstReviewDate, and SecondReview date with Calendar.TheDate so that I can do a count for all three fields for any given day.
I have tried the following code:
SELECT Employee,
Count(SubmissionDate) AS "Submissions",
Count(FirstReviewDate) AS "First Reviews",
Count(SecondReviewDate) AS "Second Reviews"
FROM Records
LEFT JOIN Calendar ON Records.SubmissionDate = Calendar.TheDate
AND Records.FirstReviewDate = Calendar.TheDate
AND Records.SecondReviewDate = Calendar.TheDate
WHERE TheDate = '2017-10-11'
All of the variations of this I have tried output nothing:
| Employee | Submissions | First Reviews | Second Reviews |
My desired code would look like this:
SELECT Employee,
Count(SubmissionDate),
Count(FirstReviewDate),
Count(SecondReviewDate)
FROM ???
WHERE TheDate = '2017-10-03'
where ??? would be the proper join. Using the desired code block (including the where clause), the desired output would like this for the example data provided:
| Employee | Submissions | First Reviews | Second Reviews |
Anne 1 2 0
Bernard 1 0 0
Charlene 0 0 0
Danielle 0 1 0
I am not sure how to do this join. I have read many resources about calendar tables, but the examples always include joining tables that each have a single date identifier. My problem is that I have one table with three date fields that need to be associated with Calendar.TheDate.
I am arranging my data like this so that the data can be visualized in Qlik Sense. I would like users to be able to select TheDate from a filter panel and have it aggregate all three fields for the date specified (essentially identical to the WHERE clause in my example code).

Answer 1

Try below code
create table #recs (
Employee varchar(10),
SubmissionDate date,
FirstReviewDate date,
SecondReviewDate date
)
insert into #recs values
('Anne', '2017-10-02', '2017-10-03', '2017-10-10'),
('Bernard', '2017-10-03', '2017-10-05', '2017-10-10'),
('Charlene', '2017-10-06', '2017-10-09', '2017-10-09'),
('Danielle', '2017-10-02', '2017-10-03', '2017-10-09'),
('Anne', '2017-10-03', '2017-10-03', '2017-10-09')
select Employee
, sum(IIF(SubD.Date_Value = #recs.SubmissionDate, 1, 0)) AS Submissions
, sum(IIF(SubD.Date_Value = #recs.FirstReviewDate, 1, 0)) AS [First Reviews]
, sum(IIF(SubD.Date_Value = #recs.SecondReviewDate, 1, 0)) AS [Second Reviews]
from #recs
left join DimDate SubD on SubD.Date_Value = '2017-10-03' and
(SubD.Date_Value = #recs.SubmissionDate
or SubD.Date_Value = #recs.FirstReviewDate
or SubD.Date_Value = #recs.SecondReviewDate)
group by Employee
If your SQL Server is older than 2012, use CASE instead of IIF
select Employee
, sum(case when SubD.Date_Value = #recs.SubmissionDate then 1 else 0 end) AS Submissions
, sum(case when SubD.Date_Value = #recs.FirstReviewDate then 1 else 0 end) AS [First Reviews]
, sum(case when SubD.Date_Value = #recs.SecondReviewDate then 1 else 0 end) AS [Second Reviews]
from #recs
left join DimDate SubD on SubD.Date_Value = '2017-10-03' and
(SubD.Date_Value = #recs.SubmissionDate
or SubD.Date_Value = #recs.FirstReviewDate
or SubD.Date_Value = #recs.SecondReviewDate)
group by Employee

Answer 2

This should work - I've included some simple DML for sample data:-
--Table Setup
IF OBJECT_ID('Records') IS NOT NULL
DROP TABLE Records;
IF OBJECT_ID('Calendar') IS NOT NULL
DROP TABLE Calendar;
CREATE TABLE Records (
Employee varchar(100),
SubmissionDate datetime,
FirstReviewDate datetime,
SecondReviewDate datetime
)
CREATE TABLE Calendar (
TheDate datetime
)
INSERT Records
VALUES ('Anne', '2017-10-02', '2017-10-03', '2017-10-10'),
('Bernard', '2017-10-03', '2017-10-05', '2017-10-10'),
('Charlene', '2017-10-06', '2017-10-09', '2017-10-09'),
('Danielle', '2017-10-02', '2017-10-03', '2017-10-09'),
('Anne', '2017-10-03', '2017-10-03', '2017-10-09')
INSERT Calendar
VALUES ('2017-10-03'), ('2017-10-04'), ('2017-10-05')
--Main Query
DECLARE #TheDate datetime = '2017-10-03'
SELECT
Employee,
SUM(CASE
WHEN c1.TheDate IS NOT NULL THEN 1
ELSE 0
END),
SUM(CASE
WHEN c2.TheDate IS NOT NULL THEN 1
ELSE 0
END),
SUM(CASE
WHEN c3.TheDate IS NOT NULL THEN 1
ELSE 0
END)
FROM Records r
LEFT JOIN Calendar c1
ON r.SubmissionDate = c1.TheDate
AND c1.thedate = #TheDate
LEFT JOIN Calendar c2
ON r.FirstReviewDate = c2.TheDate
AND c2.thedate = #TheDate
LEFT JOIN Calendar c3
ON r.SecondReviewDate = c3.TheDate
AND c3.thedate = #TheDate
GROUP BY Employee