在php中查詢非常慢（> 30s），但是在phpmyadmin中運行查詢時卻很快

Question

我認為自己是mysql / php的初學者，當您看到我的代碼：D時不要感到震驚。 我用mysql查詢制作了一個php函數，當我調用該函數時，該查詢會花費很長時間（大部分時間）。 他們很少會很快執行。 在PHPmyadmin中，此php函數中的單個查詢運行迅速且沒有錯誤。

功能慢

       public function getAllMusicDataNew($playlist_name, $mysqli) {

// einzeln alle titel / alle künstler / alle alben auflisten als array 

    $sql1 = "Select distinct title, artist, album from songs where id not in(Select distinct id from songs where id 
    IN(Select id from songs where title IN(Select title from songs where id 
    IN(Select song_id from playlist where playlist_id IN (Select playlist_id from playlists where name = '$playlist_name')))))";
    $getTitles = $mysqli->query($sql1);

    $sql2 = "Select distinct artist from songs where id not in(Select distinct id from songs where id IN
    (Select id from songs where artist IN(Select artist from songs where id IN(Select song_id from playlist
    where playlist_id IN (Select playlist_id from playlists where name = '$playlist_name')))))";
    $getArtists = $mysqli->query($sql2);

    $sql3 = "Select distinct album, artist from songs where id not in( Select distinct id from songs where id IN(Select id from songs where album IN( Select album from songs where id IN( Select song_id from playlist
    where playlist_id IN ( Select playlist_id from playlists where name = '$playlist_name'))and album <> '')))";
    $getAlbums = $mysqli->query($sql3);

    $sql4 = "Select distinct title, artist, album from songs where id in(Select distinct id from songs where id 
    IN(Select id from songs where title IN(Select title from songs where id 
    IN(Select song_id from playlist where playlist_id IN (Select playlist_id from playlists where name = '$playlist_name')))))";
    $getTitles_added = $mysqli->query($sql4);

    $sql5 = "Select distinct artist from songs where id  in(Select distinct id from songs where id IN
    (Select id from songs where artist IN(Select artist from songs where id IN(Select song_id from playlist
    where playlist_id IN (Select playlist_id from playlists where name = '$playlist_name')))))";
    $getArtists_added = $mysqli->query($sql5);

    $sql6 = "Select distinct album, artist from songs where id in( Select distinct id from songs where id IN(Select id from songs where album IN( Select album from songs where id IN( Select song_id from playlist
    where playlist_id IN ( Select playlist_id from playlists where name = '$playlist_name'))and album <> '')))";
    $getAlbums_added = $mysqli->query($sql6);


while ($row = $getTitles->fetch_assoc()) {

      $results_array1[] = $row;


    }

        while ($row = $getArtists->fetch_assoc()) {

      $results_array2[] = $row;


    }

        while ($row = $getAlbums->fetch_assoc()) {

      $results_array3[] = $row;


    }


    if(mysqli_num_rows($getTitles_added)!=0) {


        while ($row = $getTitles_added->fetch_assoc()) {

      $results_array4[] = $row;


    }


        while ($row = $getArtists_added->fetch_assoc()) {

      $results_array5[] = $row;


    }
    while ($row = $getAlbums_added->fetch_assoc()) {

      $results_array6[] = $row;


    }

    } else {


      $results_array4[] = "empty";

      $results_array5[] = "empty";

      $results_array6[] = "empty";


     }
//  print_r($titles);
        $titles["titles"] = $results_array1;
    $artists["artists"] = $results_array2;
    $albums["albums"] = $results_array3;
    $titles_added["titles_added"] = $results_array4;
    $artists_added["artists_added"] = $results_array5;
    $albums_added["albums_added"] = $results_array6;


        //  printf($array_merge($results_array1, $results_array2,      $results_array3));
            return array_merge($titles, $artists, $albums, $titles_added, $artists_added, $albums_added);


}

數據庫

-- phpMyAdmin SQL Dump
-- version 4.2.12deb2+deb8u1
-- http://www.phpmyadmin.net
--
-- Host: localhost
-- Erstellungszeit: 10. Aug 2016 um 17:04
-- Server Version: 5.5.44-0+deb8u1
-- PHP-Version: 5.6.23-0+deb8u1

SET SQL_MODE = "NO_AUTO_VALUE_ON_ZERO";
SET time_zone = "+00:00";


/*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;
/*!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */;
/*!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION */;
/*!40101 SET NAMES utf8 */;

--
-- Datenbank: `musicbox2`
--

-- --------------------------------------------------------

--
-- Tabellenstruktur für Tabelle `playlist`
--

CREATE TABLE IF NOT EXISTS `playlist` (
  `playlist_id` int(11) NOT NULL,
`track_id` int(11) NOT NULL,
  `song_id` int(11) NOT NULL,
  `votes` int(11) NOT NULL
) ENGINE=InnoDB AUTO_INCREMENT=1189 DEFAULT CHARSET=latin1;

-- --------------------------------------------------------

--
-- Tabellenstruktur für Tabelle `playlists`
--

CREATE TABLE IF NOT EXISTS `playlists` (
`playlist_id` int(11) NOT NULL,
  `name` varchar(60) NOT NULL,
  `created_at` datetime NOT NULL,
  `updated_at` datetime NOT NULL
) ENGINE=InnoDB AUTO_INCREMENT=13 DEFAULT CHARSET=latin1;

-- --------------------------------------------------------

--
-- Tabellenstruktur für Tabelle `songs`
--

CREATE TABLE IF NOT EXISTS `songs` (
`id` int(11) NOT NULL,
  `path` varchar(100) NOT NULL,
  `artist` varchar(60) NOT NULL,
  `title` varchar(60) NOT NULL,
  `album` varchar(50) NOT NULL,
  `added_at` datetime NOT NULL
) ENGINE=InnoDB AUTO_INCREMENT=4803 DEFAULT CHARSET=latin1;

-- --------------------------------------------------------

--
-- Tabellenstruktur für Tabelle `users`
--

CREATE TABLE IF NOT EXISTS `users` (
`userID` int(11) NOT NULL,
  `voices` int(11) NOT NULL,
  `pass` varchar(18) NOT NULL,
  `created_at` datetime NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

--
-- Indizes der exportierten Tabellen
--

--
-- Indizes für die Tabelle `playlist`
--
ALTER TABLE `playlist`
 ADD PRIMARY KEY (`track_id`), ADD KEY `song_id` (`song_id`), ADD KEY `playlist_id` (`playlist_id`);

--
-- Indizes für die Tabelle `playlists`
--
ALTER TABLE `playlists`
 ADD PRIMARY KEY (`playlist_id`);

--
-- Indizes für die Tabelle `songs`
--
ALTER TABLE `songs`
 ADD PRIMARY KEY (`id`), ADD UNIQUE KEY `title` (`title`,`artist`,`album`);

--
-- Indizes für die Tabelle `users`
--
ALTER TABLE `users`
 ADD PRIMARY KEY (`userID`);

--
-- AUTO_INCREMENT für exportierte Tabellen
--

--
-- AUTO_INCREMENT für Tabelle `playlist`
--
ALTER TABLE `playlist`
MODIFY `track_id` int(11) NOT NULL AUTO_INCREMENT,AUTO_INCREMENT=1189;
--
-- AUTO_INCREMENT für Tabelle `playlists`
--
ALTER TABLE `playlists`
MODIFY `playlist_id` int(11) NOT NULL AUTO_INCREMENT,AUTO_INCREMENT=13;
--
-- AUTO_INCREMENT für Tabelle `songs`
--
ALTER TABLE `songs`
MODIFY `id` int(11) NOT NULL AUTO_INCREMENT,AUTO_INCREMENT=4803;
--
-- AUTO_INCREMENT für Tabelle `users`
--
ALTER TABLE `users`
MODIFY `userID` int(11) NOT NULL AUTO_INCREMENT;
--
-- Constraints der exportierten Tabellen
--

--
-- Constraints der Tabelle `playlist`
--
ALTER TABLE `playlist`
ADD CONSTRAINT `playlist_ibfk_1` FOREIGN KEY (`song_id`) REFERENCES `songs` (`id`) ON DELETE CASCADE,
ADD CONSTRAINT `playlist_ibfk_2` FOREIGN KEY (`playlist_id`) REFERENCES `playlists` (`playlist_id`) ON DELETE CASCADE;

/*!40101 SET CHARACTER_SET_CLIENT=@OLD_CHARACTER_SET_CLIENT */;
/*!40101 SET CHARACTER_SET_RESULTS=@OLD_CHARACTER_SET_RESULTS */;
/*!40101 SET COLLATION_CONNECTION=@OLD_COLLATION_CONNECTION */;

SQL進程列表

Answer 1

使用這樣的Join查詢，我得到相同的結果及其工作:)仍然不知道為什么嵌套查詢要花費40-50秒。 感謝用戶Dibakar Paul的幫助！

$sql1 = "Select distinct title, artist, album 
from songs where id not in(Select distinct song.id
from songs song inner join playlist playlist 
on playlist.song_id=song.id
inner join playlists playlists 
on playlists.playlist_id=playlist.playlist_id
and playlists.name = '$playlist_name')";

$sql2 = "Select distinct song.title, song.artist, song.album
from songs song inner join playlist playlist 
on playlist.song_id=song.id
inner join playlists playlists 
on playlists.playlist_id=playlist.playlist_id
and playlists.name = '$playlist_name'";