MySQL查詢優化

Question

$ RES（陣列） - >（計數50（）！） 例子：

(
    [1] => Array 
     (
      [artistname] => Lady GaGa 
      [songname] => Love Games 
      [duration] => 3:31 
      [url] => 7e91a5ca16ae 
      [server] => 3 
     ) 

    [2] => Array 
     (
      [artistname] => DJ Layla 
      [songname] => Single Lady 
      [duration] => 3:20 
      [url] => f0906a3087eb 
      [server] => 3 
     ) 

    [3] => Array 
     (
      [artistname] => Lady Gaga 
      [songname] => Bad Romance (Bimbo Jones Clean Radio Remix) 
      [duration] => 3:59 
      [url] => 36e77d5a80357 
      [server] => 3 
     ) 
} 

PHP代碼：

$massquery = ''; 
foreach($res as $value) 
{ 
    if(!get_magic_quotes_gpc()) 
    { 
     $value['artistname'] = mysql_escape_string($value['artistname']); 
     $value['songname']  = mysql_escape_string($value['songname']); 
     $value['duration']  = mysql_escape_string($value['duration']); 
     $value['url']   = mysql_escape_string($value['url']); 
     $value['server']  = mysql_escape_string($value['server']); 
    } 

    $value['artistname'] = trim($value['artistname']); 
    $value['songname']  = trim($value['songname']); 
    $value['duration']  = trim($value['duration']); 
    $value['url']   = trim($value['url']); 
    $value['server']  = trim($value['server']); 

    $sh  = mysql_query("SELECT `artistname`,`songname`,`server` FROM `music` WHERE `artistname`='".$value['artistname']."' AMD `songname`='".$value['songname']."' AND `server`='".$value['server']."' LIMIT 1"); 
    if(!mysql_num_rows($sh)) 
    { 
     $massquery .= '("'.$value['artistname'].'", "'.$value['songname'].'", "'.$value['duration'].'", "'.$value['url'].'", "'.$value['server'].'"),'; 
    } 
} 

if(!empty($massquery)) 
{ 
    $massquery = substr($massquery, 0, -1); 
    $query  = mysql_query('INSERT INTO `music` (`artistname`, `songname`, `duration`, `url`, `server`) VALUES '.$massquery); 
} 
mysql_close($mysql); 

原來50個請求 「選擇」 了數據庫，這是非常不好=（ 如何優化這些代碼

從答案：

CREATE TABLE `music` (
    `id` int(50) NOT NULL auto_increment, 
    `artistname` varchar(50) NOT NULL, 
    `songname` varchar(50) NOT NULL, 
    `duration` varchar(6) NOT NULL, 
    `url` varchar(255) NOT NULL, 
    `server` int(5) NOT NULL, 
    PRIMARY KEY (`id`), 
    KEY `artistname` (`artistname`,`songname`,`server`) 
) ENGINE=MyISAM DEFAULT CHARSET=utf8; 

INSERT INTO `music` VALUES ('test', 'btest', 1); 

...

SELECT `artistname` , `songname` , `server` 
FROM `music` 
WHERE FALSE 
OR (
`artistname` = 'test' 
AND `songname` = 'btest' 
AND `server` = '1' 
) 
OR (
`artistname` = 'sas' 
AND `songname` = 'asf' 
AND `server` = '1' 
) 
LIMIT 0 , 30 

如何插入那些尚未在數據庫中的歌曲嗎？ 對不起，我的英文不好

Answer 1

要插入只有當與元組（ARTISTNAME，SONGNAME，服務器）沒有其他記錄（已經）存在的新記錄。
如果你爲這三個字段設置了create a unique index，MySQL不會插入一個doublet。然後，您可以使用類似

INSERT IGNORE INTO 
    tablename 
    (a,b,c,x,y,z) 
VALUES 
    (1,2,3,4,5,6), 
    (7,8,9,10,11,12), 
    ... 
    (95,96,97,98,99,100) 

或prepared statement，例如，

$pdo = new PDO("mysql:host=localhost;dbname=test", 'localonly', 'localonly'); 
$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); 

/* test table */ 
$pdo->exec(' 
    CREATE TEMPORARY TABLE foo (
     id int auto_increment, 
     artistname varchar(64) not null, 
     songname varchar(64) not null, 
     duration varchar(16) not null, 
     url varchar(64) not null, 
     server int not null, 
     primary key(id), 
     unique key (artistname,songname,server) 
    ) 
'); 

$data = array(
    array(':artistname' => 'Lady GaGa', ':songname' => 'Love Games', ':duration' => '3:31', ':url' => '7e91a5ca16ae', ':server' => 3), 
    array(':artistname' => 'DJ Layla', ':songname' => 'Single Lady', ':duration' => '3:20', ':url' => 'f0906a3087eb', ':server' => 3), 
    array(':artistname' => 'Lady Gaga', ':songname' => 'Bad Romance (Bimbo Jones Clean Radio Remix)', ':duration' => '3:59', ':url' => '36e77d5a80357', ':server' => 3) 
); 


/* the "actual" test script */ 
$stmt = $pdo->prepare(' 
    INSERT IGNORE INTO 
     foo 
     (duration, artistname, songname, server, url) 
    VALUES 
     (:duration, :artistname, :songname, :server, :url) 
'); 
// first run, all three records should be inserted 
foreach($data as $params) { 
    $stmt->execute($params); 
} 

// second run 
// same artist/songname, different server 
$newData = $data[0]; $newData[':server'] = 4; 
$data[] = $newData; 
// and a completly new record 
$data[] = array(':artistname' => 'xyz', ':songname' => 'The ABC song', ':duration' => '2:31', ':url' => 'whatever', ':server' => 2); 
// again insert all records (including the three that have already been inserted) 
foreach($data as $params) { 
    $stmt->execute($params); 
} 

/* fetch all records */ 
foreach($pdo->query('SELECT * FROM foo', PDO::FETCH_NUM) as $row) { 
    echo join(', ', $row), "\n"; 
} 

打印

1, Lady GaGa, Love Games, 3:31, 7e91a5ca16ae, 3 
2, DJ Layla, Single Lady, 3:20, f0906a3087eb, 3 
3, Lady Gaga, Bad Romance (Bimbo Jones Clean Radio Remix), 3:59, 36e77d5a80357, 3 
4, Lady GaGa, Love Games, 3:31, 7e91a5ca16ae, 4 
5, xyz, The ABC song, 2:31, whatever, 2 

前三記錄沒有被複制。

Answer 2

創建所有相關的情況下，像這樣一個選擇，並通過PHP來驗證結果：

$sh = "SELECT `artistname`,`songname`,`server` FROM `music` WHERE "; 
$pq = "" 
foreach($res as $value) 
{ 
if(!get_magic_quotes_gpc()) 
{ 
    $value['artistname'] = mysql_escape_string($value['artistname']); 
    $value['songname']  = mysql_escape_string($value['songname']); 
    $value['duration']  = mysql_escape_string($value['duration']); 
    $value['url']   = mysql_escape_string($value['url']); 
    $value['server']  = mysql_escape_string($value['server']); 
} 

$value['artistname'] = trim($value['artistname']); 
$value['songname']  = trim($value['songname']); 
$value['duration']  = trim($value['duration']); 
$value['url']   = trim($value['url']); 
$value['server']  = trim($value['server']); 

$sh .= $pq . `(artistname`='".$value['artistname']."' AMD `songname`='".$value['songname']."' AND `server`='".$value['server']."')"); 
$pq = " OR "; 
} 

$res = mysql_query($sh); 

Answer 3

你寫的選擇查詢不能在foreach裏面，或者它當然」每次都會查詢。把你的$資源爲長WHERE子句：

$sql = "SELECT `artistname`,`songname`,`server` FROM `music` WHERE FALSE "; 
foreach($res as $value) 
{ 
    // ... 

    $sql .= "OR (`artistname`='".$value['artistname']."' AND `songname`='".$value['songname']."' AND `server`='".$value['server'].")"; 
} 

，然後對數據庫運行該查詢，建立自己的INSERT查詢。