I see a query like
select *
from Table1
group by Step
having count(*) % 2 = 1
What is the trick about having count(*) % 2 = 1
Can anyone explain?
edit: What are the common usage areas?
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Well % is the modulo operator, which gives the remainder of a division so it would give 0 when the number is exactly divisible by 2 (even) and 1 when not (e.g. it is odd). So the query basically selects elements for which count is odd (as said above).