SELECT 
 accountno
,cs.contsupref + cs.Address1 AS 'E-Mail Address' 
FROM 
 contsupp cs
WHERE 
 (cs.CONTACT = 'E-mail Address') 
 AND (SELECT 
  CASE 
  WHEN cs.contsupref + cs.Address1  IS NULL 
  OR CHARINDEX('@.',cs.contsupref + cs.Address1 ) > 0  
  OR CHARINDEX('.@',cs.contsupref + cs.Address1 ) > 0  
  OR CHARINDEX('..',cs.contsupref + cs.Address1 ) > 0  
  OR CHARINDEX('"', cs.contsupref + cs.Address1 ) <> 0  
  OR CHARINDEX('(', cs.contsupref + cs.Address1 ) <> 0  
  OR CHARINDEX(')', cs.contsupref + cs.Address1 ) <> 0  
  OR CHARINDEX(',', cs.contsupref + cs.Address1 ) <> 0  
  OR CHARINDEX('<', cs.contsupref + cs.Address1 ) <> 0  
  OR CHARINDEX('>', cs.contsupref + cs.Address1 ) <> 0  
  OR CHARINDEX(';', cs.contsupref + cs.Address1 ) <> 0  
  OR CHARINDEX(':', cs.contsupref + cs.Address1 ) <> 0  
  OR CHARINDEX('[', cs.contsupref + cs.Address1 ) <> 0  
  OR CHARINDEX(']', cs.contsupref + cs.Address1 ) <> 0  
  OR RIGHT(RTRIM(cs.contsupref + cs.Address1 ),1) = '.'  
  OR CHARINDEX(' ',LTRIM(RTRIM(cs.contsupref + cs.Address1 ))) > 0  
  OR LEN(cs.contsupref + cs.Address1 )-1 <= CHARINDEX('.', cs.contsupref + cs.Address1 )  
  OR cs.contsupref + cs.Address1  LIKE '%@%@%'  
  OR cs.contsupref + cs.Address1  NOT LIKE '%@%.%' THEN 0 
 ELSE 1 
END) = 0