PDOStatement::fetch · W3School PHP 參考手冊

# PDOStatement::fetch PDOStatement::fetch — 從結果集中獲取下一行(PHP 5 >= 5.1.0, PECL pdo >= 0.1.0) ## 說明 ### 語法 ``` mixed PDOStatement::fetch ([ int $fetch_style [, int $cursor_orientation = PDO::FETCH_ORI_NEXT [, int $cursor_offset = 0 ]]] ) ``` 從一個 PDOStatement 對象相關的結果集中獲取下一行。fetch_style 參數決定 POD 如何返回行。 ## 參數 **fetch_style** 控制下一行如何返回給調用者。此值必須是 PDO::FETCH_* 系列常量中的一個，缺省為 PDO::ATTR_DEFAULT_FETCH_MODE 的值（默認為 PDO::FETCH_BOTH ）。 * _PDO::FETCH_ASSOC_：返回一個索引為結果集列名的數組 * _PDO::FETCH_BOTH_（默認）：返回一個索引為結果集列名和以0開始的列號的數組 * _PDO::FETCH_BOUND_：返回 **`TRUE`** ，并分配結果集中的列值給PDOStatement::bindColumn() 方法綁定的 PHP 變量。 * _PDO::FETCH_CLASS_：返回一個請求類的新實例，映射結果集中的列名到類中對應的屬性名。如果 `fetch_style` 包含 PDO::FETCH_CLASSTYPE（例如：_PDO::FETCH_CLASS | PDO::FETCH_CLASSTYPE_），則類名由第一列的值決定 * _PDO::FETCH_INTO_：更新一個被請求類已存在的實例，映射結果集中的列到類中命名的屬性 * _PDO::FETCH_LAZY_：結合使用 _PDO::FETCH_BOTH_ 和 _PDO::FETCH_OBJ_，創建供用來訪問的對象變量名 * _PDO::FETCH_NUM_：返回一個索引為以0開始的結果集列號的數組 * _PDO::FETCH_OBJ_：返回一個屬性名對應結果集列名的匿名對象 **cursor_orientation** 對于一個 PDOStatement 對象表示的可滾動游標，該值決定了哪一行將被返回給調用者。此值必須是 PDO::FETCH_ORI_* 系列常量中的一個，默認為 PDO::FETCH_ORI_NEXT。要想讓 PDOStatement 對象使用可滾動游標，必須在用 PDO::prepare() 預處理SQL語句時，設置 PDO::ATTR_CURSOR 屬性為 PDO::CURSOR_SCROLL。 **offset** 對于一個 cursor_orientation 參數設置為 PDO::FETCH_ORI_ABS 的PDOStatement 對象代表的可滾動游標，此值指定結果集中想要獲取行的絕對行號。對于一個 cursor_orientation 參數設置為 PDO::FETCH_ORI_REL 的PDOStatement 對象代表的可滾動游標，此值指定想要獲取行相對于調用 PDOStatement::fetch() 前游標的位置 ## 返回值此函數（方法）成功時返回的值依賴于提取類型。在所有情況下，失敗都返回 FALSE 。 ## 實例 ### 用不同的提取方式獲取行 ``` <?php $sth = $dbh->prepare("SELECT name, colour FROM fruit"); $sth->execute(); /* 運用 PDOStatement::fetch 風格 */ print("PDO::FETCH_ASSOC: "); print("Return next row as an array indexed by column name\n"); $result = $sth->fetch(PDO::FETCH_ASSOC); print_r($result); print("\n"); print("PDO::FETCH_BOTH: "); print("Return next row as an array indexed by both column name and number\n"); $result = $sth->fetch(PDO::FETCH_BOTH); print_r($result); print("\n"); print("PDO::FETCH_LAZY: "); print("Return next row as an anonymous object with column names as properties\n"); $result = $sth->fetch(PDO::FETCH_LAZY); print_r($result); print("\n"); print("PDO::FETCH_OBJ: "); print("Return next row as an anonymous object with column names as properties\n"); $result = $sth->fetch(PDO::FETCH_OBJ); print $result->NAME; print("\n"); ?> ``` 以上實例會輸出： ``` PDO::FETCH_ASSOC: Return next row as an array indexed by column name Array ( [NAME] => apple [COLOUR] => red ) PDO::FETCH_BOTH: Return next row as an array indexed by both column name and number Array ( [NAME] => banana [0] => banana [COLOUR] => yellow [1] => yellow ) PDO::FETCH_LAZY: Return next row as an anonymous object with column names as properties PDORow Object ( [NAME] => orange [COLOUR] => orange ) PDO::FETCH_OBJ: Return next row as an anonymous object with column names as properties kiwi ``` ### 使用一個可滾動游標獲取行 ``` <?php function readDataForwards($dbh) { $sql = 'SELECT hand, won, bet FROM mynumbers ORDER BY BET'; try { $stmt = $dbh->prepare($sql, array(PDO::ATTR_CURSOR => PDO::CURSOR_SCROLL)); $stmt->execute(); while ($row = $stmt->fetch(PDO::FETCH_NUM, PDO::FETCH_ORI_NEXT)) { $data = $row[0] . "\t" . $row[1] . "\t" . $row[2] . "\n"; print $data; } $stmt = null; } catch (PDOException $e) { print $e->getMessage(); } } function readDataBackwards($dbh) { $sql = 'SELECT hand, won, bet FROM mynumbers ORDER BY bet'; try { $stmt = $dbh->prepare($sql, array(PDO::ATTR_CURSOR => PDO::CURSOR_SCROLL)); $stmt->execute(); $row = $stmt->fetch(PDO::FETCH_NUM, PDO::FETCH_ORI_LAST); do { $data = $row[0] . "\t" . $row[1] . "\t" . $row[2] . "\n"; print $data; } while ($row = $stmt->fetch(PDO::FETCH_NUM, PDO::FETCH_ORI_PRIOR)); $stmt = null; } catch (PDOException $e) { print $e->getMessage(); } } print "Reading forwards:\n"; readDataForwards($conn); print "Reading backwards:\n"; readDataBackwards($conn); ?> ``` 以上實例會輸出： ``` Reading forwards: 21 10 5 16 0 5 19 20 10 Reading backwards: 19 20 10 16 0 5 21 10 5 ```