Question

我想知道是否可以定义表名和列名，并在php脚本中的不同sql查询中使用它们。

我尝试了一些组合：

define("USERS_TABLE", "users");
define("COLUMN_NAME", "username");

function getUserName()
{
    $dbh = new DBHandler();    
    if ($dbh->getInstance() === null) {
        die("No database connection");
    }
    try {
        $sql = "SELECT".COLUMN_NAME."FROM".USERS_TABLE"where id=1";
        $stmt = $dbh->getInstance()->prepare($sql);
        $stmt->execute();
        return $number_of_rows = $stmt->fetchColumn();
    }    
}

我也尝试过：

try {
    $sql = "SELECT :column FROM :table where id=1";
    $stmt = $dbh->getInstance()->prepare($sql);
    $stmt->bindParam(':column', COLUMN_NAME, PDO::PARAM_STR);
    $stmt->bindParam(':table', USERS_TABLE, PDO::PARAM_STR);
    $stmt->execute();
    return $number_of_rows = $stmt->fetchColumn();
}

和

define("USERS_TABLE", "users");
define("COLUMN_NAME", "username");

$tablename= USERS_TABLE;
$columnname = COLUMN_NAME;

function getUserName() use ($tablename,$columnname)
{
    try {
        $sql = "SELECT :column FROM :table where id=1";
        $stmt = $dbh->getInstance()->prepare($sql);
        $stmt->bindParam(':column', $columnname, PDO::PARAM_STR);
        $stmt->bindParam(':table', $tablename, PDO::PARAM_STR);
        $stmt->execute();
        return $number_of_rows = $stmt->fetchColumn();
    } 
}

但没有任何成功。也许不可能做这样的事情？感谢

在php中使用sql查询中定义的表和列名

0 个答案: