Where子句if null show all，if where = $variable show $variable
Where子句if null show all，if where = $variable show $variable
提问于 2014-08-29 16:41:23
我有点被我正在做的代码卡住了。
下面是我已经有的代码
HTML代码：
<form method="post" action="index.php" >
<select name="sortby" class="sortby" >
<option value=" ORDER BY id DESC">Date Added (Newest First)</option>
<option value=" ORDER BY id ASC">Date Added (Oldest First)</option>
<option value="ORDER BY clicks DESC">Website Clicks </option>
<input type="submit" value="Submit" />
</select>
</form>
<form method="post" action="index.php">
<select name="country" class="sortby">
<option value="">Country...</option>
<option value="AF">Afghanistan</option>
<option value="AL">Albania</option>
<option value="DZ">Algeria</option>
<option value="AS">American Samoa</option>
<option value="AD">Andorra</option>
.... and so on
</select>
<input type="submit" value="Submit" />PHP代码：
$sortby = $_POST['sortby'];
$sortby = $mysqli->real_escape_string($sortby);
$country = $_POST ['country'];
$country = $mysqli->real_escape_string($country);
$results = $mysqli->query("SELECT id, link, image, title, description, country, clicks FROM isc_links WHERE approved=1 $sortby");
while($row = $results->fetch_assoc()) {
print '<div id="linkmainwrapper"><div id="linkwrapper"><div class="linkimageborder"><div class="linkimage"><a href="http://'.$row["link"].'" target="_blank">'.$row["image"].'</a></div></div>';
print '<div class="linktitle"><a href="clickcounter.php?id='.$row["id"].'" target="_blank">'.$row["title"].'</a></div>';
print '<div class="link">('.$row["link"].')</div>';
print '<div class="countryflag"><img src="http://www.hatblocksdirect.co.uk/lib/flags/'.$row["country"].'.gif"></div>';
print '<div class="linkdescription">'.$row["description"].'</div>';
print '<div class="clickcount">Website Clicks ('.$row["clicks"].')</div></div></div>';我想做的是对列进行排序。第一个排序框起作用，我可以使用$sortby按网站点击量、id等进行排序。
我使用select下拉菜单传递了$country，但我不知道如何在select查询中实现它。我需要它来显示所有条目，如果一个国家还没有被选择。选择国家/地区后，仅显示该国家/地区。
非常感谢您的帮助
回答 2
Stack Overflow用户
发布于 2014-08-29 16:49:46
根据是否提供参数，将WHERE子句的附加条件放入变量中。
if (!empty($_POST['country'])) {
$country = "AND country = '" . $mysqli->real_escape_string($country) . "'";
} else {
$country = "";
}
$results = $mysqli->query("SELECT id, link, image, title, description, country, clicks FROM isc_links WHERE approved=1 $country $sortby");Stack Overflow用户
发布于 2014-08-29 16:50:06
使用if条件，如
if(isset($_POST ['country']))
{ // if country is set
$country = $mysqli->real_escape_string($_POST ['country']);
$sql="SELECT id, link, image, title, description, country, clicks FROM isc_links WHERE approved=1 and country='$country' $sortby";
}
else
{ // if country is not se
$sql="SELECT id, link, image, title, description, country, clicks FROM isc_links WHERE approved=1 $sortby";
}
$results = $mysqli->query($sql); // execute the query页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/25564668
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