PDO SQL 查询返回的行数少于预期

Question

我正在尝试从 mySQL 构建 API 到 return 的数据。我仍在努力掌握 PDO 的窍门。我有下面的查询，它应该 return 来自数据库的所有行，基于单个参数，但我注意到它经常 return 1 小于应该 returned。当有 2 行时，它 returns 1，当有 1 行时它 returns nothing.

我附上了数据库结果的屏幕截图。

如有任何建议，我们将不胜感激。

[![<?php
// required header
header("Access-Control-Allow-Origin: *");
header("Content-Type: application/json; charset=UTF-8");

// include database and object files
include_once '../config/database.php';
include_once '../objects/casualty.php';

// instantiate database and casualty object
$database = new Database();
$db = $database->getConnection();

// initialize object
$casualty = new casualty($db);

// set ID property of record to read
$casualty->id = isset($_GET\['id'\]) ? $_GET\['id'\] : die();

// query categorys
$stmt = $casualty->cemetery();
$num = $stmt->rowCount();

// check if more than 0 record found
if($num>0){

    // products array
    $casualtys_arr=array();
    $casualtys_arr\["records"\]=array();

    // retrieve our table contents
    // fetch() is faster than fetchAll()
    // 
    while ($row = $stmt->fetch(PDO::FETCH_ASSOC)){
        // extract row
        // this will make $row\['name'\] to
        // just $name only
        extract($row);

        $casualty_item=array(
            "ID" => $ID,
            "Filename" => $fldgraphicname,  
            "Surname" => $fldsurname,  
            "FirstNameInitial" => $fldfirstnameinitial  

        );

        array_push($casualtys_arr\["records"\], $casualty_item);
    }

    echo json_encode($casualtys_arr);
}

else{
    echo json_encode(
        array("message" => "No Casualties found.")
    );
}
?>
<?php
class casualty{

    // database connection and table name
    private $conn;
    private $table_name = "tblcasualty";

    // object properties
    public $id;
    public $fldgraphicname;
        public $fldsurname;
        public $fldfirstnameinitial;

    public function __construct($db){
        $this->conn = $db;
    }

    public function cemetery(){            
        // query to read single record
                    $query = "SELECT *
                        FROM 
                            tblnames 
                        WHERE
                            tblcemetery_ID = ?
                            ORDER BY ID
                         ";
        $stmt = $this->conn->prepare( $query );

        // bind id of product to be updated
        $stmt->bindParam(1, $this->id, PDO::PARAM_INT);

        // execute query
        $stmt->execute();

        // get retrieved row
        $row = $stmt->fetch(PDO::FETCH_ASSOC);

        // set values to object properties
        $this->fldgraphicname = $row\['fldgraphicname'\];
        $this->fldsurname = $row\['fldsurname'\];
        $this->fldfirstnameinitial = $row\['fldfirstnameinitial'\];    

            return $stmt;
    }        

}
?>][1]][1]

Answer 1

在你的 cemetery 函数中你有一个 fetch。这会将光标前进一个位置，因此当您返回主脚本并使用 fetch 时，您总是在第二行。

解决方案：

在函数中循环 fetch 并且只是 return 所有值的数组。

或

不要 fetch 函数和 return 结果集，这样你就可以 fetch 整个块。

PDO SQL 查询返回的行数少于预期

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