SQL Pivot - Dynamic Columns, No Aggregation - sql

Question

I'm trying to do a Pivot, but I'm not very experienced with pivots and I'm stuck - I can't figure out how to structure the query.
What I have:
Data Types (types of measurements that are recorded)
Locations
Data Sources (things at each location that will be measured)
Data Readings (measurements of the sources)
Additional information:
The number of Sources at any one Location can change
There will never be more than 5 sources at a single Location
Only 1 Reading is saved per Source/Type/date
In the returned table:
Table shows Data_Type info and Readings for a single Location and date
Columns: Data_Name, Units, Is_Required (from Data_Type table), plus one column for each Source
Rows: one row for each Data_Type
Rows should be ordered by Type_Display_Order
Sources (extra columns) should be ordered by Source_Display_Order
Some Readings are optional, and some Sources aren't measured daily - these still need to be included in the table
Example:
Table: Data_Type
Data_Type_ID Data_Name Units Is_Required (BIT) Type_Display_Order
-----------------------------------------------------------------------
1 Height In. 1 2
2 Length In. 0 3
3 Weight Lbs. 1 1
Table: Location
Location_ID Location
-----------------------
1 West
2 East
Table: Data_Source
Data_Source_ID Location_ID Source_Name Source_Display_Order
----------------------------------------------------------------
1 1 WCS 2
2 2 ECS 1
3 1 WBN 1
Table: Data_Reading
Data_Reading_ID Data_Type_ID Data_Source_ID Reading Reading_Date
----------------------------------------------------------------------
1 1 1 5 6/3/2016
2 3 2 3 5/1/2016
3 1 1 7 5/1/2016
4 2 3 2 6/3/2016
5 3 1 4 6/3/2016
Desired results from query for Location = "West", Date = 6/3/2016:
Data_Type_ID Data_Name Units Is_Required WBN WCS
---------------------------------------------------------
3 Weight Lbs. 1 NULL 4
1 Height In. 1 NULL 5
2 Length In. 0 NULL NULL
This solution seems to be similar: Pivot Dynamic Columns, no Aggregation but I'm still having some problems.
This is what I have so far:
DECLARE #date DATE, #locationID INT
SET #date = CAST('6/3/2016' AS DATE)
SET #locationID = 1
DECLARE #cols AS NVARCHAR(MAX), #query AS NVARCHAR(MAX)
SET #cols = STUFF((SELECT distinct ',' + QUOTENAME(s.Source_Name)
FROM Data_Source s
WHERE s.Location_ID = #locationID
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)')
,1,1,'')
SET #query = 'SELECT Data_Type_ID, Data_Name, Units, Is_Required, ' + #cols +
' FROM
(
SELECT
t.Data_Type_ID
, t.Data_Name
, t.Units
, t.Is_Required
, r.Reading
, s.Source_Name
FROM
Data_Type t
LEFT JOIN
Data_Reading r ON t.Data_Type_ID = r.Data_Type_ID
LEFT JOIN
Data_Source s ON r.Data_Source_ID = s.Data_Source_ID
WHERE
r.Reading_Date = CAST(CAST(' + #date + ' AS NVARCHAR(10)) AS DATE)
AND s.Location_ID = CAST(' + #locationID + ' AS INT)
) x
PIVOT
(
MIN(Reading)
for Source_Name in (' + #cols + ')
) p '
I have the query working properly now, but I still have a few problems:
#cols is not sorted by Source_Display_Order
rows are not sorted by Type_Display_Order (I did have ORDER BY in the inner SELECT statement for part X, but I was getting errors saying I can't have an ORDER BY clause there)
Date comparison in WHERE statement doesn't work - for some reason, it always computes as False, even when the dates are the same

Answer 1

Solved!
DECLARE #date DATE, #locationID INT
SET #date = CAST('6/3/2016' AS DATE)
SET #locationID = 1
DECLARE #cols AS NVARCHAR(MAX), #query AS NVARCHAR(MAX)
SET #cols = STUFF((SELECT ',' + QUOTENAME(s.Source_Name)
FROM Data_Source s
WHERE s.Location_ID = #locationID
ORDER BY s.Source_Display_Order
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)')
,1,1,'')
SET #query =
'SELECT
Data_Type_ID
, Data_Name
, Units
, Is_Required
, ' + #cols + '
FROM
(
SELECT
t.Data_Type_ID
, t.Data_Name
, t.Units
, t.Is_Required
, r.Reading
, s.Source_Name
, t.Type_Display_Order
FROM
Data_Type t
LEFT JOIN
Data_Reading r ON t.Data_Type_ID = r.Data_Type_ID
LEFT JOIN
Data_Source s ON r.Data_Source_ID = s.Data_Source_ID
WHERE
r.Reading_Date = ''' + CAST(#date AS NVARCHAR(10)) + '''
AND s.Location_ID = ' + CAST(#locationID AS NVARCHAR(20)) + '
) x
PIVOT
(
MIN(Reading)
for Source_Name in (' + #cols + ')
) p
ORDER BY
Type_Display_Order'
EXECUTE(#query)
To fix my problems:
Convert #date to NVARCHAR before adding to #query string and include extra quotes to surround the new NVARCHAR in quotes within #query
Remove DISTINCT clause from #cols and add ORDER BY (all of the names in my table are unique, so the DISTINCT is unnecessary)
Add Type_Display_Order to the inner SELECT statement, and add ORDER BY after the PIVOT statement