作爲一個愛好項目,我開始爲一家公司製作一個網站。我在製作複雜的網站代碼方面並不是很先進,但我想嘗試一下。如何加快MySQL中的Haversine公式?
我有一個荷蘭郵政編碼數據庫,其中有超過471000條記錄。我使用haversine公式來查找哪些郵政編碼位於13 km的半徑範圍內,然後從數據庫中選擇每個用戶在此結果中具有郵政編碼。但公式需要6秒來加載所有結果。我怎樣才能加快這個過程呢?下面
代碼:
$finder = $mysqli->query("SELECT lat, lng FROM postcodetabel WHERE postcode = '$s' OR plaats = '$s'");
$finder1 = mysqli_fetch_assoc($finder);
$latitude = $finder1['lat'];
$longitude = $finder1['lng'];
$query = $mysqli->query("SELECT postcode, (
6371 * acos (
cos (radians('$latitude'))
* cos(radians(lat))
* cos(radians(lng) - radians('$longitude'))
+ sin (radians('$latitude'))
* sin(radians(lat))
)
) AS distance
FROM postcodetabel
HAVING distance < 12
ORDER BY distance ASC");
$quertie = $mysqli->query("SELECT bigav, id, naam, email, bedrijfsnaam, telnummer FROM gebruikers WHERE postcode = '$postcode' AND status = 1 AND soort LIKE '%" . $soort . "%'");
while($quertie2 = mysqli_fetch_assoc($quertie)) { echo '
<div class="kapper">
<div class="kapperfoto"><img src="/vluggeknipt/ondernemer/pagina/uploads/'.$quertie2['bigav'].'" style="width:100px;height:100px;"></div>
<div class="boektekst">
<font class="headingkap"><strong><a href="?page=profiel&id='.$quertie2['id'].'">Naar profiel »</a></strong></font><br/>
</div>
<div class="kappertext">
<font class="headingkap"><a href="?page=profiel&id='.$quertie2['id'].'"><strong>'.$quertie2['naam'].'</strong></a></font><br/>
<i class="mobhide">'.$quertie2['email'].' - '.$quertie2['telnummer'].'</i><br/>
<i class="mobhide">'.$quertie2['bedrijfsnaam'].'</i>
</div></div><br/>
'; }
在此先感謝!
很好的答案!你可以(/任何人)指出這種方法合理準確的距離上限嗎?說,在正確答案的5%以內? – richplane