update data via php in mysql DB -

i have looked on www , forum, not find answer work. want update post on .........../post.php?id=19

this function:

function update_user($conn) {      if(isset($_get['id'])) {         $id = $_get['id'];         $name = $_post['name'];         $age = $_post['age'];         $sql = "update users set name =':name', age = ':age' id=':id'";         $query = $conn->prepare($sql);         $query->execute( array( ':name'=>$name, ':age'=>$age, ':id' => $id ));         }  } 

and form:

 <h3>update user</h3>  <?php update_user($conn) ?>  <form name="myform2" method="post" action= "">  <label>name:</label><input type="text" id="name" name="name">  <label>age:</label><input type="text" id= "age" name="age">   <input type="submit" value="add" name="update"> 

i have no errors post returns old record without update filled in form.

hope can assist me, million. bas

ps. $conn correct , works when insering or printing posts.

couple issues is, 1 view profile page $_get['id'] set, execute update_user function regardless if form submitted or not. should check value ensure form submitted. other issue sql named parameters should not use quotes.

<?php function update_user($conn) {     if(isset($_post['id'])) {         $id = $_post['id'];         $name = $_post['name'];         $age = $_post['age'];         $sql = "update users set name = :name, age = :age id = :id";         $query = $conn->prepare($sql);         $query->execute(array(':name' => $name, ':age' => $age, ':id' => $id));     } } ?>   <h3>update user</h3>  <?php update_user($conn) ?>  <form name="myform2" method="post" action= "">  <label>name:</label><input type="text" id="name" name="name">  <label>age:</label><input type="text" id= "age" name="age">  <input type="hidden" name="id" value="<?php echo $_get['id'] ?>">  <input type="submit" value="add" name="update">  </form> 

i added hidden input field id , changed condition update_user check post id instead of id.

and love of programming, please validate $_post data before sending database.