php - 使用 PDO 执行高级搜索查询的问题

Question

我有以下代码，除了标题字段之外，所有搜索功能都可以工作。所以我可以按类型、日期、地点等搜索……但不能按标题搜索。当尝试按标题搜索时，根本不会返回任何内容。谁能帮我解决这个问题吗？

此外，是否有更有效的方法来计算所有字段，然后再将其限制用于稍后的分页？

$today = date("Y-m-d");
$query = "SELECT * FROM TABLE_NAME WHERE Date >= '$today'";

$bind = Array();

if ($_GET["Title"] && $_GET["Title"] != "") {
    $query .= " and Title like %?%";
    $bind['Title'] = $_GET['Title'];
}
if ($_GET["Genre"] && $_GET["Genre"] != "") {
    $query .= " and Genre like %?%";
    $bind['Genre'] = $_GET['Genre'];
}
if ($_GET["Location"] && $_GET["Location"] != "") {
    $query .= " and Location like %?%";
    $bind['Location'] = $_GET['Location'];
}
if ($_GET["Date"] && $_GET["Date"] != "") {
    $query .= " and Date = %?%";
    $bind['Date'] = $_GET['Date'];
}

$stmt = $db->prepare($query);
$stmt->execute($bind);
$rows = $stmt->fetchAll(PDO::FETCH_ASSOC);
$num = count($rows);

$query .= " ORDER BY Date LIMIT $limit, 9";
$stmt = $db->prepare($query);
$stmt->execute($bind);
$rows = $stmt->fetchAll(PDO::FETCH_ASSOC);

编辑:在大家的帮助下，我想我应该发布我现在修改后的代码以供将来引用。事实证明，其他字段不起作用，而是由于 if 语句，所有嵌套在代码中的内容根本没有被执行。

$today = date("Y-m-d");
$query = "SELECT * FROM TABLE_NAME WHERE Date >= '$today'";
$countq = "SELECT count(*) FROM TABLE_NAME WHERE Date >= '$today'";

$bind = Array();

if ($_GET["Title"] && $_GET["Title"] != "") {
    $query .= " and Title like :title";
    $countq .= " and Title like :title";
    $bind[':title'] = "%{$_GET['Title']}%";
}
if ($_GET["Genre"] && $_GET["Genre"] != "") {
    $query .= " and Genre like :genre";
    $countq .= " and Genre like :genre";
    $bind[':genre'] = "%{$_GET['Genre']}%";
}
if ($_GET["Location"] && $_GET["Location"] != "") {
    $query .= " and Location like :loc";
    $countq .= " and Location like :loc";
    $bind[':loc'] = "%{$_GET['Location']}%";
}
if ($_GET["Date"] && $_GET["Date"] != "") {
    $query .= " and Date = :date";
    $countq .= " and Date = :date";
    $bind[':date'] = "{$_GET['Date']}";
}

$stmt = $db->prepare($countq);
$stmt->execute($bind);
$rows = $stmt->fetchAll();
$num = count($rows);

$query .= " ORDER BY Date LIMIT $limit, 9";
$stmt = $db->prepare($query);
$stmt->execute($bind);
$rows = $stmt->fetchAll(PDO::FETCH_ASSOC);

Answer 1

all of the search functions work

对于给定的查询，它不正确

来自PDO tag wiki :

placeholders cannot represent an arbitrary part of the query, but a complete data literal only. Neither part of literal, nor whatever complex expression or a syntax keyword can be substituted with prepared statement.

Prepare FULL literal first: $name = "%$name%"; and then bind it.

至于“更”有效的分页方法 - 是的，哦，是的。
使用当前的数据计数方式，您实际上不需要其他查询。因为您已经拥有所有数据并且也可以对其进行分页。
但当然它很快就会污染所有的内存。因此，如果您想从数据库中获取行数，请获取具体计数:运行相同的查询，但不要使用 SELECT * 而是使用 "SELECT count(*)

There are not any errors returned, that's why I am so confused

再次来自 PDO 标签 wiki:

It is essential to set ERRMODE_EXCEPTION as a connection option as it will let PDO throw exceptions on connection errors. And this mode is the only reliable way to handle PDO errors.