Query Result Help

Hi,all,
I ran the two queries and I thought it would be the same, but it's different.
Can you explain to me.

Query 1: result---52 rows
select s.InsuredSurname, s.email from studyUSA s
join interMedical I on s.email=I.email
where convert(char(10), s.enrolldate, 126)>= '2004-01-01'
and convert(char(10), s.enrolldate, 126) <='2005-05-20'
and (s.agentcode not like '162%') and (s.agentcode not like '17%')
and s.agentcode <> '130844'


Query 2: result--14 rows

select s.InsuredSurname, s.email from tis_studyUSA s
where convert(char(10), s.enrolldate, 126)>= '2004-01-01'
and convert(char(10), s.enrolldate, 126) <='2005-05-20'
and s.email IN (Select I.Email from tis_InterMedical I)
and (agentcode not like '162%') and (agentcode not like '17%')
and agentcode <> '130844'

Thanks!
Betty