在 pdo 中绑定多个数组

用于生成动态查询的代码存在问题。构建动态查询时，需要将查询的静态部分与动态部分分开。

您可以看到以下代码是静态的。

$query = "SELECT
        b.id,   
        b.`name`,
        b.`year`,
        GROUP_CONCAT(DISTINCT a.`name`) AS author_names,
        GROUP_CONCAT(DISTINCT s.`name`) AS store_names,
        'book' as param
    FROM
        books AS b
        LEFT JOIN books_authors AS b_a ON b.id = b_a.book_id
        LEFT JOIN authors AS a ON a.id = b_a.author_id
        LEFT JOIN books_stores AS b_s ON b.id = b_s.book_id
        LEFT JOIN stores AS s ON s.id = b_s.store_id ";

而且

" GROUP BY b.id
  ORDER BY b.id";   

代码的其余部分是动态的。过滤记录时，使用 WHERE 子句，并使用 AND 和 OR 运算符根据多个条件过滤记录。如果第一个条件和第二个条件都为真，则 AND 运算符将显示一条记录。如果第一个条件或第二个条件为真，则 OR 运算符将显示一条记录。所以对于第一个条件，使用了 WHERE，但之后必须使用 AND 或 OR（在您的示例中使用 OR）

// Static code
sql = "SELECT * FROM `table`"
// Set initial condition to WHERE       
clause = "WHERE";       
if( !empty( filter )){
    Add clause to sql 
    Add condition to sql
    change clause to OR or AND as required
}
Repeat for each filter
Note the filter is not changed until a filter is  not empty and remains changed once changed.
The remaining static code is added after all the filters have been handled

要允许应用不同的过滤器，您可以使用标志。

$flag = 0;
if(isset($_POST['books'])){
    $books_ids = $_POST["books"];
    $flag += 1;
}
if(isset($_POST['authors'])){
    $authors_ids = $_POST["authors"];
    $flag += 10;
}
if(isset($_POST['stores'])){
    $stores_ids = $_POST["stores"];
    $flag += 100;
}

尽可能使用"惰性"绑定 - 将数据传递到执行将大大缩短代码。查看 PDO 信息您需要合并数组才能执行此操作。使用带有标志的 switch 语句可以合并所需的数组。

switch ($flag) {
    case 1:
        $param_array = $books_ids;
        break;
    case 10:
        $param_array = $authors_ids;
        break;
    case 100:
        $param_array = $stores_ids;
        break;
    case 11://books & authors
        $param_array = array_merge($books_ids, $authors_ids); 
        break;
    case 101://books & stores
        $param_array = array_merge($books_ids, $stores_ids); 
        break;
    case 110://authors & stores
        $param_array = array_merge($authors_ids, $stores_ids); 
        break;
     case 111://books & authors & stores
        $param_array = array_merge(array_merge($books_ids,$authors_ids),$stores_ids);
        break;  
}
if( !empty( $query )) {
    $stmt = $conn->prepare($query); 
    $stmt->execute($param_array);
    $results = $stmt->fetchAll();
    echo json_encode($results);
}

以下代码使用上述要点。我已经回显了一些行来指示测试完成后可以删除的结果。此外，一些代码已被注释掉以进行测试。

//Set flag
$flag = 0;
if(isset($_POST['books'])){
    $books_ids = $_POST["books"];
    $flag += 1;
}
if(isset($_POST['authors'])){
    $authors_ids = $_POST["authors"];
    $flag += 10;
}
if(isset($_POST['stores'])){
    $stores_ids = $_POST["stores"];
    $flag += 100;
}
echo $flag. " <BR>";//Remove after testing
//Basic SQL statement 
$query = "SELECT
        b.id,
        b.`name`,
        b.`year`,
        GROUP_CONCAT(DISTINCT a.`name`) AS author_names,
        GROUP_CONCAT(DISTINCT s.`name`) AS store_names,
        'book' as param
    FROM
        books AS b
        LEFT JOIN books_authors AS b_a ON b.id = b_a.book_id
        LEFT JOIN authors AS a ON a.id = b_a.author_id
        LEFT JOIN books_stores AS b_s ON b.id = b_s.book_id
        LEFT JOIN stores AS s ON s.id = b_s.store_id ";
// Set initial condition to WHERE       
$clause = "WHERE";      
if( !empty( $books_ids ))
{
    $books_ids_in = implode(',', array_fill(0, count($books_ids), '?'));
    $query .= $clause;
    $query .= " b.id IN (". $books_ids_in .")";
    // Set condition to OR for additional condition
    $clause = " OR ";   
}
if( !empty( $authors_ids ) )
{
    $authors_ids_in = implode(',', array_fill(0, count($authors_ids), '?'));
    /*  This part commented out as I don't see relevance
        if (!empty($query)) {
         $query .= " UNION ";
    }
    */
    $query .= $clause;
    $query .= "    b.id IN (
            SELECT DISTINCT book_id FROM books_authors WHERE author_id IN (". $authors_ids_in .")
            )";
    // Set condition to OR for additional condition     
    $clause = " OR ";       
}

if( !empty( $stores_ids ) )
{
    $stores_ids_in = implode(',', array_fill(0, count($stores_ids), '?'));
    /* if (!empty($query)) {
         $query .= " UNION ";
    }
    */
    $query .= $clause;
    $query .= " b.id IN (
            SELECT DISTINCT book_id FROM books_stores WHERE store_id IN (". $stores_ids_in .")
            )";
    $clause = " OR ";
}
//Add GROUP & ORDER
    $query .= " GROUP BY b.id
    ORDER BY b.id";
echo $query; //Remove after testing
//building $param_array
switch ($flag) {
    case 1:
        $param_array = $books_ids;
        break;
    case 10:
        $param_array = $authors_ids;
        break;
    case 100:
        $param_array = $stores_ids;
        break;
    case 11://books & authors
        $param_array = array_merge($books_ids, $authors_ids); 
        break;
    case 101://books & stores
        $param_array = array_merge($books_ids, $stores_ids); 
        break;
    case 110://authors & stores
        $param_array = array_merge($authors_ids, $stores_ids); 
        break;
     case 111://books & authors & stores
        $param_array = array_merge(array_merge($books_ids,$authors_ids),$stores_ids);
        break;  
}
echo "<br>";
print_r($param_array);// remove after testing
/*
if( !empty( $query )) {
    $stmt = $conn->prepare($query); 
    $stmt->execute($param_array);
    $results = $stmt->fetchAll();
    echo json_encode($results);
}
$conn = null;

不要使用相同的$k; 使用变量并随着每个绑定而递增;见下文

$bindingIndex = 0;
if( !empty( $books_ids ))
{
    foreach ($books_ids as $k => $id) {
        $stmt->bindValue((++$bindingIndex), $id);
    }
}
if( !empty( $authors_ids ))
{
    foreach ($authors_ids as $k => $id) {
        $stmt->bindValue((++$bindingIndex), $id);
    }
}
if( !empty( $stores_ids ))
{
    foreach ($stores_ids as $k => $id) {
        $stmt->bindValue((++$bindingIndex), $id);
    }
}