PHP PDO SQL只返回一行数据而不是所有行

Question

I am using PHP PDO extension to create a list of all items from a DB category table. The expected results are not correct, only one row of data returned instead of all rows which is expected. By running the same SQL statement within the phpMyAdmin console I get the expected results for all rows of data. I need to know what I am overlooking with pdo.

Current code:

    $catId = 0;   

    $sql = "SELECT *
            FROM category
            WHERE cat_parent_id = :catId
            ORDER BY cat_name";

    $_stmt = $this->_dbConn->prepare($sql);
    $_stmt->bindParam(":catId", $catId, PDO::PARAM_INT);  
    $_stmt->execute();

    $rows = $_stmt->fetch(PDO::FETCH_ASSOC);    

    // display PDO result - only getting one row instead of all rows.       
    print_r($rows);

    Array ( [cat_id] => 3 
            [cat_parent_id] => 0 
            [cat_name] => Shop 
            [cat_description] => Seminars 
            [cat_image] => c72e.gif 
            )

    // NOTE: By running the same SQL within the phpMyAdmin 
    // console I get the expected results with all rows.
    Array ( [cat_id] => 3 
            [cat_parent_id] => 0 
            [cat_name] => Shop 
            [cat_description] => Seminars 
            [cat_image] => c72e.gif 
           ),
          ( [cat_id] => 1 
            [cat_parent_id] => 0 
            [cat_name] => Site Map 
            [cat_description] => List content links 
            [cat_image] => c83b.gif 
           )

Answer 1

PDOStatement::fetch() will only return 1 row at a time.

You could use PDOStatement::fetchAll():

$rows = $_stmt->fetchAll(PDO::FETCH_ASSOC);

or create a loop where you keep calling PDOStatement::fetch() until it returns false:

$rows = array();
while( $row = $_stmt->fetch(PDO::FETCH_ASSOC) ) {
  $rows[] = $row;
}

But the latter example is a bit redundant, if you want to get all rows at once anyway, unless there are some memory concerns you want to address.