examples/prime.html

﻿<!DOCTYPE html>
<head>
	<title>Prime-numbers test alasql.js database</title>
	<script src="../alasql.js"></script>
</head>
<body>
	<h1>Test of alasql.js database: Prime Numbers with Sieve of Eratosthenes</h1>

	<p><a href="http://stackoverflow.com/questions/12461896/make-function-call-wait-for-web-sql-query">Original source</a></p> 

	<div id="res"></div>

	<script>
		var tm = Date.now();

		var db = new alasql.Database();
		db.exec('CREATE TABLE primes (prime INT)');

		function primecheck (number) {
		    var isprime = true;
	        if (number%10 == 1 || number%10 == 3 || number%10 == 7 || number%10 == 9) {
	            db.exec('SELECT * FROM primes', [], function (result) {
	                for (var i = 1; i < result.length; i++) {
	                    if (number%result[i].prime == 0) {
	                        isprime = false;
	                        break;
	                    }
	                }
	                if (isprime) {
	                    db.exec('INSERT INTO primes (prime) VALUES ('+number+')');
	                }
	                return isprime;
	            });
	        } else {
		        isprime = false;
		        return isprime;
		    }
		}

		var maxnum = 1000;
		for(var i=1; i<maxnum;i++) {
			primecheck(i);
		};

		var cnt = db.exec('SELECT COUNT(prime) AS cnt FROM primes GROUP BY prime')[0].cnt;
		var res = db.exec('SELECT * FROM primes');

		var s = '<p>There are '+cnt+' prime numbers less than '+maxnum+': <br> '+res.map(function(p){return p.prime}).join(', ')+'</p><p>Time '+(Date.now()-tm)+' ms </p>';

		document.getElementById('res').innerHTML = s;
	</script>
</body>