小编Rip*_*or 的帖子

我在PHP中使用PDO对象来运行MYSQL查询,我一直在尝试处理查询以加快它的速度.查询如下,如我的PHP文件中所示:

$query = 
"SELECT SQL_NO_CACHE f.position, s.item_id, s.item_type, s.title, s.caption, s.date
FROM apiv2.search_all s 
INNER JOIN apiv2.tags t 
USING(item_id, item_type) 
LEFT JOIN apiv2.featured f 
ON t.item_id = f.item_id AND t.item_type = f.item_type AND f.feature_type = :id 
WHERE t.tag = 'FeaturedContent'
ORDER BY position IS NULL, position ASC, date";

$mysql_vars[':id'] = $id;
$stmt = $connection->prepare($query);
$stmt->execute($vars);
$data = $stmt->fetchAll(PDO::FETCH_ASSOC);

此查询的运行方式有很大不同,具体取决于我是否包含ORDER BY子句,但仅限于MYSQL控制台:

 - MYSQL Console with ORDER BY: 1.07 sec
    - starting  0.000141
    - Opening tables    0.001416
    - System lock   0.000003
    - …

尝试使用在MySQL服务器上运行SQL查询的PHP脚本将数据库复制到新数据库中.我所熟悉的代码是:

$dbh->exec("CREATE DATABASE IF NOT EXISTS $new_news CHARACTER SET UTF8;");
$results = $dbh->query("SHOW TABLES FROM $old_news");
$table_list = $results->fetchAll(PDO::FETCH_NUM);

foreach($table_list as $table_row){
    foreach($table_row as $table){
        $results = $dbh->query("SELECT table_type FROM information_schema.tables where table_schema = '$old_news' and table_name = '$table'");
        $table_type = $results->fetch(PDO::FETCH_ASSOC);
        $table_type = $table_type['table_type'];
        if($table_type == 'BASE TABLE'){
            echo "Creating table $table and populating...\n";
            $dbh->exec("CREATE TABLE $new_news.$table LIKE $old_news.$table");
            $dbh->exec("INSERT INTO $new_news.$table SELECT * FROM $old_news.$table");
        }else if($table_type == 'VIEW'){
            //echo "Creating view $table...\n";
            //$dbh->exec("CREATE VIEW $new_news.$table LIKE $old_news.$table"); …