问SQL试图识别以10位数开头的行。

EN

WITH
 locmembers(member_id, email_address) AS
 (SELECT 1,'12345@rrr.com' FROM dual UNION ALL   --numbers but < 10 digits
  SELECT 2,'1122334455@rrr.com' FROM dual UNION ALL  --numbers = 10 digits
  SELECT 3,'112233445566@rrr.com' FROM dual UNION ALL  --numbers > 10 digits
  SELECT 4,'emailaddress@rrr.com' FROM dual UNION ALL
  SELECT 5,'emailsaddress1122334455@rrr.com' FROM dual   --email address with 10 digits
 )
SELECT
 member_id
,email_address
,SUBSTR(REGEXP_REPLACE(email_address, '^[[:digit:]]{10}' ),1,1)
FROM
 locmembers
WHERE SUBSTR(REGEXP_REPLACE(email_address, '^[[:digit:]]{10}' ),1,1) = '@'
;