Hi!
Try this. It might work for you.
SELECT
T0.[CardCode], T0.[CardName], T2.[SlpCode], T1.[Name], T1.[E_MailL], T2.[SlpName]
FROM OCRD T0
INNER JOIN OCPR T1 ON T0.CardCode = T1.CardCode
INNER JOIN OSLP T2 ON T0.SlpCode = T2.SlpCode
WHERE LEFT(T1.[E_MailL],LEN(T2.[SlpName])) <> T2.[SlpName]
Regards,
