How to write a query for PHP and MySQL?

how to write php MySql query

• I would like to be able to make a selection from a select-box and view the selected table. My skill level with php/MySQL at this point is: $query = "SELECT * FROM electrical ORDER BY item_id LIMIT $offset, $RPP"; With this query the div is populated on page load. I have a select box that has 6 choices: <form> <select name="dbtables" onchange="showTable(this.value)" id="selectBox"> <option value="">Select a materials table:</option> <option value="" id="hr"></option> <option value="equipment">Worker Equipment</option> <option value="tool">General Tools</option> <option value="electrical">Electrical Materials</option> <option value="mechanical">Mechanical Materials</option> <option value="plumbing">Plumbing Materials</option> <option value="hvac">HVAC Materials</option> </select> </form> Each choice is a table in a single MySQL database. Script for showTable is working, after making selection alert shows choice picked. function showTable(str) { if (str == "") { document.getElementById("materials").innerHTML = ""; return; } if (window.XMLHttpRequest) { // code for IE7+, Firefox, Chrome, Opera, Safari xmlhttp = new XMLHttpRequest(); } else { // code for IE6, IE5 xmlhttp = new ActiveXObject("Microsoft.XMLHTTP"); } xmlhttp.onreadystatechange = function () { if (xmlhttp.readyState == 4 && xmlhttp.status == 200) { document.getElementById("materials").innerHTML = xmlhttp.responseText; } } xmlhttp.open("GET", "index.php?q=" + str, true); xmlhttp.send(); alert(str); } Any pointers or help is appreciated appreciated.

• Answer:

  in your index.php pick the $str value using $_GET method and construct the query. then run that query and echo the data. after that, you can call this function in the script file after alert(). function useHttpResponse() { if (http.readyState == 4) { if(http.status == 200) { var txt = http.responseText; var response_msg="<h4><span class='darkblue'>" + txt + "</span></h4>" document.getElementById('showtime').innerHTML = response_msg; } } else { //you may skip this else portion document.getElementById('showtime').innerHTML = '<img src="images/loading.gif" /><span class="darkblue">retrieving data...</span>'; } } here your fetched data will show on a div with id "showtime". during the fetching the time a loading gif will be visible in the "showtime" div. or you may skip that else portion. hope that function will help you.