php isset question

[houssam_ballout]

Hello all,I've built a single page, that retrieves a data from database.For example, on the php page, I've added the link:<a href='test1.php?id=1'>anything </a><a href='test1.php?id=2'>anything </a>when I click on one of it, I want the next page to display the results from sql query, but I don't know how to use it id (like: id=1) from the isset, to use it??Any help

[Anders Moen]

You mean like this?

$id = intval($_GET['id']);$q = mysql_query("SELECT * FROM pages WHERE id = '$id'");$row = mysql_fetch_assoc($q);echo 'Welcome to this page called ' . htmlentities(stripslashes($row['title']));

[houssam_ballout]

Well, I'd a table with ID, title, and contents fieldsI had page name called display.php, and 3 links inside it display1.php?id=1......................=2......................=3For example, if I clicked on first link, I must get the records where ID=1 inthe database, but how can I know via isset which link did the user presses?

[Mr_CHISOL]

First, isset() only checks if a variable/value is set or not:

if (isset($_GET['id']))  // $_GET['id'] exists/is setif (isset($foo))  // $foo exists/is set

Second: Take a look at Anders' code again, that's what you are looking for.values from the querystring (the values after ? in the URL) is stored in $_GET, say you go to file.php?id=42&foo=bart&more=less and the code looks like this:

$id = intval($_GET['id']);  // intval makes sure that you get a integer, nothing else.// The variable $id now contains 42// We could also display it like this:$foo = $_GET['foo'];echo 'ID:' . $id . ', ' . $_GET['id'] . '; foo:' . $foo . ', ' . $_GET['foo'] . '; bar:' . $_GET['bar'] . '; more:' . $_GET['more'] . "\n";

The code would output something like this:

ID:42, 42; foo:bart, bart; bar:;more:less

There's no value by bar:, because bar isn't set in the querystring.If we would try with this link instead file.php?id=42lol&foo=bart&bar=more, the output would be:

ID:42, 42lol; foo:bart, bart;bar:more;more:

now you see two different values for ID, first 42 and then 42lol (which is the value you gave it in the querystring), this is beacuse we used intval() on $_GET['id'] when we stored it in $id, which makes it to an integer, and the second value of id is "pure", directly from the querystring. Now we also see a value of bart, but no value for more, as we removed it...Hope that helped...

[teng84]

you may use the if statement and the switch statementsample if ($_GET[id]==1) do this else do that the other is switch switch ($_GET[id]) case '1':dothisbreak;case '2':do thatbreak;