How to select from two tablse from the database

[bokivaol]

What is command to connect two tables from the database. I would like to select from table "newsletter" all emails which are different AND  to select from the table "user_registration" all users with newsletter=1, but if there any user in those two tables with the same email, I would not like to display it twice.

When I put in the code

$s = dbQuery("select * from `newsletter` where `email`<>'' order by `email`");

- it display all different emails from the table "newsletter"

When I put in the code

$s = dbQuery("select * from `user_registration` where `newsletter`='1' order by `email`");

- it display all emails from the table "user_registration" with newsletter=1.

I would like to connect these two equations, but I don't know how, I don't know what is command? Can you help me about this? I used JOIN command, but I didn't do anything.

 

<?php
        $s = dbQuery("select * from `user_registration` where `newsletter`='1' order by `email`");........1        
        /* $s = dbQuery("select * from `newsletter` where `email`<>'' order by `email`");........................2*/
        $count = dbNumRows($s);
        if($count>0){
        ?>
        <select size="6" multiple="multiple" id="multi" name="multi[]" style="width:200px;">
        <?php        
            while($t = dbFetchArray($s,MYSQL_BOTH))
            {    
        ?>
            <option value="<?php echo $t["id"]; ?>"><?php echo $t["email"]; ?></option>
        <?php
            }        
        ?>
        <?php
            }        
        ?>   
        </select>
        <input type="checkbox" onClick="selectAll(this);"/> Select All<br />
        <input type="submit" onclick="return checkdel();" name="DelUser" value="Delete Those Subscribers" />
        <?php
        }
        else
        {
        ?>
        No Records!
        <?php
        }        
        ?>

 

Can anyone help me to write a code, I am not so good in mysql and php, but I know what I want.

 

[attachment deleted by admin]

[fenway]

You're looking for a join.

[bokivaol]

Maybe it is easy for you, but for me it is very hard. I tried with

SELECT newsletter.email, user_registration.email FROM user_registration LEFT JOIN newsletter ON newsletter.email <> user_registration.email

, but I need function IF and THEN. IF they are = THEN display just ONE of them, all other different emails should be displayed.

[bokivaol]

I solved problem.

I used UNION function:

"(SELECT `email` FROM `user_registration` WHERE `newsletter`='1') UNION (SELECT `email` FROM `newsletter`) ORDER BY `email`"