How do you ensure accuracy of your query I am have a table with about 100,000 rows.

Lets suppose the primary key is some sequence of numbers like a barcode for example.

I am doing checks like 

SELECT count(*) FROM TABLE WHERE LEFT(Barcode, 1)  is 0


I have about a 100 more rules to implement. They should ALL return 0 rows. But how do I ensure that they are returning 0 rows because the data is in fact correct OR that it is returning 0 rows because of a poorly written query. 

I know that all my queries should return 0 since there are constraints that prevent bad data from getting in the first place but this is still needed by the company.
You can do this pretty easily using SUM and CASE:

SELECT 
    COUNT(*) as 'Total Rowcount',
    SUM(CASE WHEN LEFT(BARCODE, 1) = 0 THEN 1 ELSE 0 END) as 'Leading Zero Barcode',
    SUM(CASE WHEN LEFT(Foo, 1) = 'X' THEN 1 ELSE 0 END) as 'Leading X in Foo'
....


Then you get a number for the WHOLE table/query, and a breakdown of each category, all on the same line.  It'll be easy to see if you have a bad query since you'll get a low/high rowcount or something else.

This has the added advantage or processing more efficiently than a bunch of separate queries, since you just evaluate the whole table once.