Table Company(
  CompanyId NVarChar(10) Not Null Constraint PK_Locations Primary Key,
  CompanyName NVarChar(30),
  CompanyAddress NVarChar(30),
  CompanyCity NVarchar(30),
  CompanyState Char(2),
  CompanyZip NVarChar(10),
  DateCreated DateTime,
  LastModified DateTime,
  LastModifiedUser NVarChar(64)
)

WITH q AS (
          SELECT Company.*,
                 ROW_NUMBER() OVER (PARTITION BY CompanyState, CompanyCity, CompanyName ORDER BY CompanyID) AS rnName,
                 ROW_NUMBER() OVER (PARTITION BY CompanyState, CompanyCity, CompanyAddress ORDER BY CompanyID) AS rnAddress
          FROM Company
          )
SELECT    *
WHERE     rnName > 1 OR rnAddress > 1

CompanyID    CompanyName  CompanyAddress
---------    -----------  --------------
1            McDonalds    Avenue 1
2            McDonalds    Avenue 2
3            Starbucks    Avenue 2

SELECT  *
FROM    Company co
WHERE   EXISTS
        (
        SELECT  1
        FROM    Company cn
        WHERE   cn.CompanyState = co.CompanyState
                AND cn.CompanyCity = co.CompanyCity
                AND cn.CompanyName = co.CompanyName
                AND cn.CompanyID <> co.CompanyID
        )
        OR EXISTS
        (
        SELECT  1
        FROM    Company ca
        WHERE   ca.CompanyState = co.CompanyState
                AND ca.CompanyCity = co.CompanyCity
                AND ca.CompanyAddress = co.CompanyAddress
                AND ca.CompanyID <> co.CompanyID
        )

SELECT
     C1.CompanyID,
     C2.CompanyID
FROM
     Company C1
INNER JOIN Company C2 ON
     (C2.CompanyName = C1.CompanyName OR C2.CompanyAddress = C1.CompanyAddress) AND
     C2.CompanyCity = C1.CompanyCity AND
     C2.CompanyState = C2.CompanyState AND
     C2.CompanyID > C1.CompanyID

Select field1, field2, ... etc, count(*)
FROM Company,
GROUP BY field1, field2, ...
HAVING count(*) > 1