How to select domain name from email address

Question

I have email addresses like user1@gmail.com, user2@ymail.com user3@hotmail.com ... etc. I want a Mysql SELECT that will trim user name

Answer 1

Using SUBSTRING_INDEX for "splitting" at '@' and '.' does the trick. See documentation at http://dev.mysql.com/doc/refman/5.1/de/string-functions.html#idm47531853671216.

SELECT SUBSTRING_INDEX(SUBSTRING_INDEX(email, '@', -1), '.', 1);

Example:

SELECT SUBSTRING_INDEX(SUBSTRING_INDEX("foo@bar.buz", '@', -1), '.', 1);

will give you "bar".

Here is what happens:
* Split "foo@bar.buz" at '@'. --> ["foo", "bar.buz"]
* Pick first element from right (index -1). --> "bar.buz"
* Split "bar.buz" at '.' --> ["bar", "buz"]
* Pick first element (index 1) --> "bar"
Result: "bar"

If you also need to get rid of subdomains, use:

SELECT SUBSTRING_INDEX(SUBSTRING_INDEX(SUBSTRING_INDEX(email, '@', -1), '.', -2), '.', 1);

Example:

SELECT SUBSTRING_INDEX(SUBSTRING_INDEX(SUBSTRING_INDEX("foo@1.2.3.bar.buz", '@', -1), '.', -2), '.', 1);

will give you "bar".