Use your mouse? There's a symbol in the bottom left hand corner of it so you can increase the size:

So you can do:

Use an SP. Putting the SQL directly in SSRS is rarely a good idea.

Also, however, I doubt that using several temporary tables is going to be the best...

Interesting idea Eirikur. If I read your code correctly, however, this does assume that the value between the the Greater Than symbols is only 1 character.

One idea:

WITH Grps AS (
  SELECT SS.str_raw,
    DS.Item,
    DS.ItemNumber,
    ROW_NUMBER() OVER (PARTITION BY SS.str_raw ORDER BY DS.ItemNumber) -
    ...

Did they run anything else when they did it as well? Running an INSERT statement afterwards and leaving it in situ is going to be more problematic than simply opening...

Have to say it, but a classic example of the type of person that'll post something desperate: https://www.sqlservercentral.com/Forums/1932589/Determining-the-Years-Months-Weeks-and-Days-between-two-dates

Then 20(ish) minutes later, the OP thinks: "I haven't had...

Personally, i think Phil's suggestion earlier is the winner. Check if the rogue column exists first, if it doesn't use the dataflow that doesn't require it, if it does, use...