Sort of... the answer (well, it's PowerBI and DAX, so of course Marco Russo answered it on YouTube...)

In case anybody is interested, it's here: Managing hierarchical organizations in Power...

Okay, guess I have some reading to do. The basic idea is that any node on the tree can see all his underlings, but nothing above that, and nothing on...

Disclaimer: I'm not a DBA.

But, have you read Gail Shaw's T-SQL Howler about Partitioning? If you haven't read it, you owe it to yourself to do so before doing...

Cast as Decimal?

SELECT CAST(154399.234 AS DECIMAL(17,2));

Maybe use PowerQuery to normalize? Then import the result of that? At least then you could set your source to a folder and do a folder full at once.

It depends on what rights the users have on the database. Say you create a view or stored procedure and grant them execute rights only, you could create a source...

What are your end users going to do with the file? The one thing that stinks about the Get Data option is that it "assumes" you're going to add it...

One way of solving this problem is to create a view or stored procedure (depends on whether you need parameters) and then grant a group rights to execute the query....

use Tableau.  yeah, just kidding. kind of.

Use Drill Through. I'm pretty sure Patrick LeBlanc (GuyInACube, Freeze) did a video on it and it's on YouTube somewhere.

there are videos all over on YouTube. You need drillthrough.  Pretty sure Adam and Patrick have several videos about it. Search for GuyInACube.

A table with that many columns makes me wonder what the table is describing. it's hard to imagine storing that many bits of information about each instance of a thing....

Why not a simple .NET form to insert into a SQL Server table?

that's an odd request. Did you create a stored procedure to transform the table somehow? Could you post the SQL for it? I'm asking because you don't need SSRS for...

I want to calculate the percentage and aggregate only if the percentage is => 75%

You have to use FILTER() for that, because that's the only way to filter a table...

LAG() basically does what you're describing - goes back N rows in the window.