What does the following query return?

select

mt1.AcctNo,

mt1.Mdate,

count(*) as RecCnt

from

dbo.MyTable01 mt1

inner join dbo.MyTable2 mt2

on (m1.AcctNo = mt2.AcctNo

and m1.Mdate = mt2.Mdate)

group by

mt1.AcctNo,

mt1.Mdate

having

count(*) > 1

order by

mt1.AcctNo,

mt1.Mdate;