count distinct
select PaidInID,count(distinct SignInstitutionName) from PI_PaidInMonthlyEmployeeExtra group by PaidInID having count(distinct SignInstitutionName) > 1
select PaidInID,count(distinct SignInstitutionName) from PI_PaidInMonthlyEmployeeExtra group by PaidInID having count(distinct SignInstitutionName) > 1