Re: Different Count(distinct) in the same query

[Rick James]

First a comment on the schema... Today, you have types a,b,c; tomorrow you will have a,b,c,d. What will you do? The answer is that you should have those columns (%_txn and %_currency) in another table with multiple rows as needed.

I'm confused as to what you are doing, but here are some tips:
SUM(b_txn <> 0) -- counts the number of rows with b_txn <> 0
GROUP BY customer -- may be necessary

Please provide SHOW CREATE TABLE

You want txn=45 -- please show us which numbers add up to 45.