使用PDO獲取上一行下一行創建鏈接

Question

我在查詢中遇到了一些不好的聯繫，我試圖創建'prev_id'來拉入$行結果鏈接。有沒有更好的方法來做到這一點？

編輯：錯誤是「檢查對應於您的MySQL服務器版本的手冊，以找到'prev_id'附近使用的正確語法。」

function traversePhoto($the_selected_id) { 
global $pdo; 

$id = $the_selected_id; 

$stmt_a = $pdo->prepare(" 
    (SELECT * FROM images WHERE id < '.intval($id).' ORDER BY id DESC LIMIT 1) 
    UNION (SELECT * FROM images WHERE id = (SELECT MAX(id) FROM images)) LIMIT 1 prev_id"); 
$stmt_b = $pdo->prepare(" 
    (SELECT * FROM images WHERE id > '.intval($id).' ORDER BY id ASC LIMIT 1) 
    UNION (SELECT * FROM images WHERE id = (SELECT MIN(id) FROM images)) LIMIT 1 next_id"); 

// $vars = array(':id' => $id); 
$prev = $stmt_a->execute(); 
$next = $stmt_b->execute(); 

if ($prev) { 
    while($row = $stmt_a->fetchObject()) { 
     echo '<a href="' . $row['prev_id'] . '">Previous</a>'; 
    } 
} else { 
    echo 'no previous'; 
} 

if ($next) { 
    while($row = $stmt_b->fetchObject()) { 
     echo '<a href="' . $row['next_id'] . '">Next</a>'; 
    } 
} else { 
    echo 'no next'; 
} 

}

Answer 1

嘗試像這樣

<?php function traversePhoto($the_selected_id) { 
global $pdo; 

$id = $the_selected_id; 

$stmt_a = $pdo->prepare(" 
(SELECT * FROM images WHERE id < ? ORDER BY id DESC LIMIT 1) 
UNION (SELECT * FROM images WHERE id = (SELECT MAX(id) FROM images)) LIMIT 1"); 
$stmt_b = $pdo->prepare(" 
(SELECT * FROM images WHERE id > ? ORDER BY id ASC LIMIT 1) 
UNION (SELECT * FROM images WHERE id = (SELECT MIN(id) FROM images)) LIMIT 1"); 

// $vars = array(':id' => $id); 
$prev = $stmt_a->execute(array((int)$id)); 
$next = $stmt_b->execute(array((int)$id)); 

if ($stmt_a->rowCount() > 0) { 
    while($row = $stmt_a->fetch(PDO::FETCH_ASSOC)) { 
     echo '<a href="' . $row['prev_id'] . '">Previous</a>'; 
    } 
} else { 
    echo 'no previous'; 
} 

if ($stmt_b->rowCount() > 0) { 
    while($row = $stmt_b->fetch(PDO::FETCH_ASSOC)) { 
     echo '<a href="' . $row['next_id'] . '">Next</a>'; 
    } 
} else { 
echo 'no next'; 
}