DM-42324: Fix min/max rows logic for Deduplication.

[TallJimbo]

Checklist

• ran Jenkins
• added a release note for user-visible changes to doc/changes (not user-visible)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (7fe8783) 99.50% compared to head (3d10fe9) 99.50%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #11   +/-   ##
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  Coverage   99.50%   99.50%           
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  Files          15       15           
  Lines        1216     1224    +8     
  Branches      102      102           
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+ Hits         1210     1218    +8     
  Misses          4        4           
  Partials        2        2           

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[dhirving]

Out of curiosity why can this ever be '1' instead of '0'? Doesn't no columns also imply no rows?

[TallJimbo]

Not quite; if you think of it as a list of dict rows it's the difference between [] and [{}]. But where it really matters is actually in what happens when you join a relation like this to a regular one with nonzero numbers of rows and columns: [{}] is the "join identity" - a join between it and any other relation is the other relation, while [] is the "join zero" relation - a join between it and any other relation yields a relation with no rows (but the other relation's columns).