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SELECT items in TABLE 1 but not in TABLE 2
Posted by: coke coke
Date: April 16, 2008 01:20AM

Hi again, I'm noob and I'm building a web tool to send custom messages to the users like welcome messages, offer, reminder and so on...

I'm using a simple structure with 3 tables

user:users table,
email: custom messages
posta: history of sended messages

mysql> describe posta;
+------------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+------------+--------------+------+-----+---------+----------------+
| id | int(11) | | PRI | NULL | auto_increment |
| email | int(11) | YES | | NULL | |
| dest | varchar(250) | YES | | NULL | |
| data_invio | datetime | YES | | NULL | |
| destid | int(11) | YES | | NULL | |
+------------+--------------+------+-----+---------+----------------+

In the table POSTA I have email (the id of message sended, and destid is the user id receved it).


Now I'm not able to write the right query to know the user list to send the message "April news".

For example...

April news message is in the email table with the id 7, so I check the POSTA TABLE (the history of sended message) and I have 2 user just receved that message. I don't want to send double message to that users!

mysql> select id,email,destid from posta where destid >0;
+----+-------+--------+
| id | email | destid |
+----+-------+--------+
| 72 | 7 | 3 |
| 73 | 7 | 260 |
+----+-------+--------+
2 rows in set (0.03 sec)


I wrote something like that

SELECT user.id from user,posta WHERE user.id != posta.destid and posta.email = 7 group by user.id;

But the result il the complete list of user i have. It is wrong!

Maybe it is simple but I'm noob... can you help me ?



ps. This is a second post I wrote, I hope to have explain my question better then last one, I'm sorry for that becouse I was not able to delete that message [NEWBIE] JOIN... and I don't want to spam this forum with my noob question. Sorry sorry and sorry!

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SELECT items in TABLE 1 but not in TABLE 2
April 16, 2008 01:20AM


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