Problem with JOIN query

[cms9651]

Hello guys!
I need your help.

I have tow table in MYSQL:

1. tbl_login 5.739 rows, alias A;
2. tbl_mailing_list 3.736 rows, alias B

The field to be related tbl_login (A) and tbl_mailing_list (B) is e`email`.
I need to know any emails of the table B are not present in table A and try this query:

SELECT
	A.email,
	B.email
FROM
	tbl_mailing_list A
JOIN tbl_login B ON A.email = B.email

2690 rows in set

but these are the lines that have emails matching between the two tables...

Thank you for the suggestion.

[r937]

"rows in one table not present in another" = LEFT OUTER JOIN with IS NULL test

SELECT B.email
  FROM tbl_login B
LEFT OUTER
  JOIN tbl_mailing_list A
    ON A.email = B.email
 WHERE A.email IS NULL

in order to prevent these situations from happening, you need to learn about foreign keys

[cms9651]

thank you for your help.

I tried your suggestion, but in the output I have all email present in the tbl_login and not present in tbl_mailing_list.

I need the opposite:
all email present in the tbl_mailing_list and not present in tbl_login.

[r937]

oh shoot, i did it the wrong way around, sorry

okay, just reverse the tables in the LEFT OUTER JOIN

[cms9651]

Ok , thank you.
This is the new output:

SELECT B.email
  FROM tbl_mailing_list B
LEFT OUTER
  JOIN tbl_login A
    ON A.email = B.email
 WHERE A.email IS NULL

Time: 0.031ms
1039 rows in set

I try this other query and I have the same output.
What is the difference?
What is the most performant?

SELECT
	email
FROM
	tbl_mailing_list
WHERE
	email NOT IN (SELECT email FROM tbl_login);

Time: 0.031ms
1039 rows in set

[r937]

What is the difference?

no difference in output

What is the most performant?

interesting question

sometimes NOT IN subqueries are slower

this time it appears they performed the same

[cms9651]

thanks a lot!