在一个查询语句中将2个表连接在一起

Question

Im trying to join two tables together becouse 2 columns match and i need info from second table to display the content. When i pressing a link with ?p=1a i want content to show and this info i have on the second table but not the first one. Where table 1 and table 2 match on column Menu. I have shorten down on some code/table info becouse its not relevant for this problem. im then displaying the info with mysql_fetch_assoc.

TABLE 1

MENU | subtitle | firstname |info

info | contact

word | woord

TABLE 2

MENU | page |

info | 1a

word | 1b

My code:

if(isset($_GET['p'])){
    $page = $_GET['p'];

    $find = mysqli_query("SELECT * FROM testcheck, testdoc INNER JOIN testdoc ON testcheck.Menu = testdoc.MENU AND page='$page' ");
    while($row = mysqli_fetch_assoc($find)){
        $subtitle = $row['subtitle'];
        $firstname = $row['firstname'];
        echo $firstname
    }
}

Problem is correct kinda now but only letters work fine but when i combine page='1a' for example everything stop works.

Answer 1

Your syntax for the join is wrong.

Use:

"SELECT * FROM testcheck
INNER JOIN testdoc ON testcheck.Menu = testdoc.MENU AND page='$page'
");

Answer 2

Read more about LEFT JOIN and RIGHT JOIN . In your case you would need RIGHT JOIN to get data that is in second table but not in first.

Like popovitsj suggested your syntax is also wrong.

Correct syntax:

SELECT * FROM testcheck
INNER JOIN testdoc ON testcheck.Menu = testdoc.Menu AND page='$page'

Also note that you are using MENU upper case which is not a problem on windows but will be a problem on unix, it will give you an error Column Not Found.

EDIT

If your table has column MENU then it should be fine.