Select Data for excel Graph sees zeroes when I load the data using sql - excel

Question

I have a problem with Excel (2016)/ VBA macros. I am happy to provide more detail or copies of files if required.
In summary this is what is happening:
I have a workbook with five worksheets. Three contain data representing both axes of a matrix (1&2), the cells of the matrix (3), one sheet on which data from sheets 1 to 3 are brought together (4) and - finally - a graph worksheet (5 - based on a range in 4).
The reason I do it like this is that I want to graph parts of the data at a time otherwise it is all too confusing. A simple form is used to choose which column of the data-set to display and to also allow stepping through the list of items to display so just part of the range is in view at a time. Variables are set in cells on sheet 4 (outside the graphed range) when the buttons are clicked on the form. The formulae that populate the graphed range on that sheet use these variables to choose the required data from sheets 1 to 3.
Initially I populated the data in sheets 1 to 3 using macros to read from text files. These files had to be populated from a database before opening the Excel workbook. I decided to "Simplify" this process by changing the macros to query the database directly.
It took a while to get this going and all looked fine. I can see the data in the first four worksheets is populated correctly (including being able to click on the form buttons and change the contents of the graphing range) but the graph sees values of zero in every cell. When I right click on the graph and select "Select Data" and then choose an item in the "Legend Entries (Series)" list in the left-hand box, and the click "Edit", I see the cell ranges of both the Series name and the Series Values are correctly displayed, the preview of "Name" has the correct value but the preview of "Series" shows a string of comma-separated zeroes.
I can switch worksheets to view the "GraphData" on sheet 4 while still keeping the dialogue box open and see the actual cells that are being referred to and they are not 0, 0, 0... they are 78, 69, 44...
Where are the zeroes coming from?
I have even saved the workbook - keeping changes - so the contents of sheets 1 to 3 are kept, put a stop in the "Workbook_Open" macro so it doesn't run, and still I get zeroes when I re-open it.

Answer 1

Sorry to bother folk. I worked out the problem. As usual, there were interesting lessons along the way.
I started out with a query that populated a text file with data from my database. Because I wanted the file to be ingested by Excel as a csv file, the output for each row of the selected data was a single string column containing the keys and the data values with commas between them, the numbers being converted to VARCHAR within the sql so I could concatenate them into the string.
Them when I decided to try using the query directly from Excel rather than having the file step in between, I removed the concatenation operators and the commas and put a comma between them in the sql syntax but didn't remove the conversion to VARCHAR of the numbers.
With QueryTable, when you import a text file, one of the optional properties is an array of codes representing the data types of the incoming data. I assumed that with a direct query, Excel would assign a data type based on content as it does for typed values (unless you specify another). Clearly Excel and the source database exchange information, in addition to the data set itself, that tells Excel the data type of the columns - as sent.
The graphing function was seeing my data as strings so assigned values of zero. I began by putting a Value() around my lookup functions on the GraphData worksheet. That worked but then I went further back and actually changed the Sql so it sent numeric data without conversion to VARCHAR and then it worked without the Value() change.
It never occurred to me that Excel wouldn't just see a number and treat it as such - not that Sql Server would have told Excel it was a string.