Sql script to find invalid email addresses

Here is a quick and easy solution:

CREATE FUNCTION dbo.vaValidEmail(@EMAIL varchar(100))

RETURNS bit as
BEGIN     
  DECLARE @bitRetVal as Bit
  IF (@EMAIL <> '' AND @EMAIL NOT LIKE '_%@__%.__%')
     SET @bitRetVal = 0  -- Invalid
  ELSE 
    SET @bitRetVal = 1   -- Valid
  RETURN @bitRetVal
END 

Then you can find all rows by using the function:

SELECT * FROM users WHERE dbo.vaValidEmail(email) = 0

If you are not happy with creating a function in your database, you can use the LIKE-clause directly in your query:

SELECT * FROM users WHERE email NOT LIKE '_%@__%.__%'

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