提高复杂 SQL 查询的性能
Improve performance of complex SQL query
几个月以来，我一直在从公开来源收集足球比赛的数据。为此，我通过 XPath 使用 PHP 获取特定网站 URL 的数据，该网站显示特定足球比赛的数据。然后我进行一些数据编辑，使它们符合我需要的方式。下一步也是最后一步是在 table 秒内将它们传输到我的 MySQL 数据库中。
随着数据库的快速增长，我慢慢地 运行 遇到了严重的性能问题。因为我在我的电脑上本地做所有事情而且那台机器不是怪物，所以处理一场比赛已经需要一些时间。感受一下这有多快：在数据挖掘的最初几天，一场比赛大约需要 24 秒。但是，现在平均值超过了 60 秒的阈值。
到目前为止，我偶尔会研究 PHP 代码并尝试在可能的情况下对其进行改进，因为我认为主要问题在于不太干净的代码片段。虽然它有点帮助，但平均时间在几天后进一步增加，最近我开始意识到必须有另一个耗时的问题。所以我制作了一个测试 PHP 脚本，它在 运行 运行主代码时执行某种日志记录。
它表明我为将数据插入数据库 table 所做的一些 SQL 查询平均花费大量时间（我在这里分析了 100 个匹配项）：
- 数据库中的首发阵容：6.44 秒
- DB 替补队员：8.49 秒
再次检查查询，我发现它们非常复杂。
涉及的 table 个：
tblStartingSquad
+----+---------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+------------+------------+--------+
| id | matchID | player1ID | player2ID | player3ID | player4ID | player5ID | player6ID | player7ID | player8ID | player9ID | player10ID | player11ID | clubID |
+----+---------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+------------+------------+--------+
| 1 | 1 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 1 |
| 2 | 1 | 12 | 13 | 14 | 15 | 16 | 17 | 16 | 17 | 18 | 19 | 20 | 2 |
| 3 | 2 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 1 |
| 4 | 2 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 3 |
+----+---------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+------------+------------+--------+
tblSubstitutes
+----+---------+------------+------------+------------+------------+------------+------------+------------+------------+------------+------------+------------+------------+--------+
| id | matchID | player12ID | player13ID | player14ID | player15ID | player16ID | player17ID | player18ID | player19ID | player20ID | player21ID | player22ID | player23ID | clubID |
+----+---------+------------+------------+------------+------------+------------+------------+------------+------------+------------+------------+------------+------------+--------+
| 1 | 1 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 1 |
| 2 | 1 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 2 |
| 3 | 2 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 1 |
| 4 | 2 | 56 | 57 | 58 | 59 | 60 | 61 | 61 | 62 | 63 | 64 | 65 | 66 | 3 |
+----+---------+------------+------------+------------+------------+------------+------------+------------+------------+------------+------------+------------+------------+--------+
tblMatch
+---------+---------------------+-------------+------------------+
| matchID | date | coach1 | coach2 |
+---------+---------------------+-------------+------------------+
| 1 | 2006-08-19 22:00:00 | Piotr Nowak | Fernando Clavijo |
| 2 | 2006-08-15 21:00:00 | Piotr Nowak | Mustafa Ugur |
+---------+---------------------+-------------+------------------+
tblPlayer
+----------+------------------------+------------------+
| playerID | namePlayer | short |
+----------+------------------------+------------------+
| 1 | Enis Ulusan | enis-ulusan |
| 2 | Grant Robert Murray | grant-murray |
| 3 | Evgeniy Shpedt | evgeniy-shpedt |
| 4 | Mihai Alexandru Costea | mihai-costea |
| 5 | Jan Zolna | jan-zolna |
| 6 | Adrian Gheorghiu | adrian-gheorghiu |
| 7 | Marius Marian Croitoru | marius-croitoru |
| 8 | Jacov Nachtailer | jacov-nachtailer |
| ... | ... | ... |
+----------+------------------------+------------------+
tblClub
+--------+-----------------+
| clubID | nameClub |
+--------+-----------------+
| 1 | D.C. United |
| 2 | Colorado Rapids |
| 3 | Caykur Rizespor |
+--------+-----------------+
这些是涉及的查询：
SQL查询首发阵容
$tblstarting_squad = 'INSERT INTO tblStartingSquad (matchID, player1ID, player2ID, player3ID, player4ID, player5ID, player6ID, player7ID, player8ID, player9ID, player10ID, player11ID, clubID)
SELECT
(SELECT matchID FROM tblMatch WHERE date = "' . $match_date . '" AND coach1 = "' . $match_coach_home . '" AND coach2 = "' . $match_coach_away . '"),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[0] . '" AND short = "' . $player_short[0] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[1] . '" AND short = "' . $player_short[1] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[2] . '" AND short = "' . $player_short[2] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[3] . '" AND short = "' . $player_short[3] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[4] . '" AND short = "' . $player_short[4] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[5] . '" AND short = "' . $player_short[5] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[6] . '" AND short = "' . $player_short[6] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[7] . '" AND short = "' . $player_short[7] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[8] . '" AND short = "' . $player_short[8] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[9] . '" AND short = "' . $player_short[9] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[10] . '" AND short = "' . $player_short[10] . '" LIMIT 1),
(SELECT clubID FROM tblClub WHERE nameClub = "' . $match_club[1] . '" LIMIT 1)
WHERE NOT EXISTS (
SELECT e.matchID
FROM tblStartingSquad As e
INNER JOIN tblMatch As m
ON e.matchID = m.matchID
WHERE m.date = "' . $match_date . '" AND m.coach1 = "' . $match_coach_home . '" AND m.coach2 = "' . $match_coach_away . '" AND e.clubID = (SELECT clubID FROM tblClub WHERE nameClub = "' . $match_club[1] . '")
);';
if (!mysqli_query($db_connection, $tblstarting_squad)) {
echo("Error description $tblstarting_squad: " . mysqli_error($db_connection) . "<br />");
}
SQL 查询替补球员
$tblsubstitutes = 'INSERT INTO tblSubstitutes (matchID, player12ID, player13ID, player14ID, player15ID, player16ID, player17ID, player18ID, player19ID, player20ID, player21ID, player22ID, player23ID, clubID)
SELECT
(SELECT matchID FROM tblMatch WHERE date = "' . $match_date . '" AND coach1 = "' . $match_coach_home . '" AND coach2 = "' . $match_coach_away . '"),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[11] . '" AND short = "' . $player_short[11] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[12] . '" AND short = "' . $player_short[12] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[13] . '" AND short = "' . $player_short[13] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[14] . '" AND short = "' . $player_short[14] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[15] . '" AND short = "' . $player_short[15] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[16] . '" AND short = "' . $player_short[16] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[17] . '" AND short = "' . $player_short[17] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[18] . '" AND short = "' . $player_short[18] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[19] . '" AND short = "' . $player_short[19] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[20] . '" AND short = "' . $player_short[20] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[21] . '" AND short = "' . $player_short[21] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[22] . '" AND short = "' . $player_short[22] . '" LIMIT 1),
(SELECT clubID FROM tblClub WHERE nameClub = "' . $match_club[1] . '" LIMIT 1)
WHERE NOT EXISTS (
SELECT e.matchID
FROM tblSubstitutes As e
INNER JOIN tblMatch As m
ON e.matchID = m.matchID
WHERE m.date = "' . $match_date . '" AND m.coach1 = "' . $match_coach_home . '" AND m.coach2 = "' . $match_coach_away . '" AND e.clubID = (SELECT clubID FROM tblClub WHERE nameClub = "' . $match_club[1] . '")
);';
if (!mysqli_query($db_connection, $tblsubstitutes)) {
echo("Error description $tblsubstitutes: " . mysqli_error($db_connection) . "<br />");
}
这两个查询实际上是相同的。如果没有其他条目具有相同的数据，他们将 11 个（分别为 12 个）玩家的 playerID 插入 tblStartingSquad（分别为 tblSubstitutes）。 playerID 必须事先在数据库中检查，因为原始数据没有个人 ID。通过 namePlayer 和 short 从 table tblPlayer.
选择它
tables tblStartingSquad 和 tblSubstitutes 本身目前包含 110,000 行（55,000 个匹配），tblPlayer 是 100,000 行。
我在谷歌上搜索了一些解决方案，但没能找到任何可以提高整体速度的方法。我理解的一个问题是我必须单独检查每个玩家，所以我得到 11 和 12 个子查询。这不是很优雅，但我真的不知道如何改进它。也许 Whosebug 上有人有建议？
正如 O.Jones 在评论中所述，查看更多 (php) 代码有助于判断性能问题。
尽管重新设计了您的数据库，但另一个快速建议实际上是 运行 一个循环并使用 prepared statement 来对玩家 ID 进行单独查询。这可能会给您带来轻微的性能提升。
在我看来确实合乎逻辑，在 PHP 中做更多而不是将数据获取逻辑外包给 SQL。
重新考虑您的 wide table 设计以实现 long table 设计。带编号后缀的列从来都不是理想的数据存储。行很便宜。色谱柱很贵。连接、聚合、搜索、索引等在长格式中要容易得多。否则，您的查询将很复杂，因为您显示有 12 个子查询甚至自连接！
有趣的是，您的 tblClub 和 tblPlayer 是长格式但 tblStartingSquad 和 tblSubstitutes！简单地说，将所有无关的玩家列删除到 one 中，其中行表示不同的玩家：
tblStartingSquad
ID MatchID PlayerID ClubID
1 1 5 1
2 1 8 1
3 1 9 1
...
tblSubstitutes
ID MatchID PlayerID ClubID
1 1 2 1
2 1 16 1
3 1 7 1
...
tblMatch （为清楚起见重命名了教练列）
ID Date HomeCoach AwayCoach
1 2006-08-19 22:00:00 Piotr Nowak Fernando Clavijo
2 2006-08-15 21:00:00 Piotr Nowak Mustafa Ugur
PHP
从这个数据库设计中，您可以 运行 一个更简单的 PHP 参数化查询调用，使用 PDO 更容易，而不是 mysqli 来绑定来自数组。
// OPEN CONNECTION
$dbconn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
// SET PDO ERROR MODE TO EXCEPTION
$dbconn -> setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
// PREPARED STATEMENT
$sql = "INSERT INTO tblStartingSquad (`Match`, `PlayerID`, `ClubID`)
SELECT m.MatchID, p1.PlayerID, c.ClubID
FROM
(SELECT p.PlayerID
FROM tblPlayer p
WHERE p.namePlayer IN (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
) p1
INNER JOIN
(SELECT p.PlayerID
FROM tblPlayer p
WHERE p.short IN (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
) p2 ON p1.PlayerID = p2.PlayerID
CROSS JOIN
(SELECT MatchID
FROM tblMatch
WHERE `date` = ? AND HomeCoach = ? AND AwayCoach = ?) m
CROSS JOIN
(SELECT ClubID
FROM tblClub
WHERE nameClub = ?) c
WHERE NOT EXISTS
(SELECT 1 FROM tblStartingSquad As e
WHERE e.MatchID = m.matchID)"
try {
// INITIALIZE STATEMENT
$stmt = $dbconn->prepare($sql);
$params = array($player_name[0], $player_name[1], $player_name[2],
$player_name[3], $player_name[4], $player_name[5],
$player_name[6], $player_name[7], $player_name[8],
$player_name[9], $player_name[10],
$player_short[0], $player_short[1], $player_short[2],
$player_short[3], $player_short[4], $player_short[5],
$player_short[6], $player_short[7], $player_short[8],
$player_short[9], $player_short[10],
$match_date, $match_coach_home, $match_coach_away, $match_club);
// ITERATIVELY BIND PARAMS
foreach($params as $key => $val) {
$stmt->bindParam($key+1, $val, PDO::PARAM_STR);
}
// EXECUTE ACTION
$stmt->execute();
} catch (PDOException $e) {
echo "Error: " . $e->getMessage();
}
对 tblSubstitutes 进行类似的调用，调整追加查询的目标和 WHERE 子句和参数值。
语句并不复杂。它们只包含大量查找。因此，请确保查找速度很快。您需要以下索引。如果您还没有它们，请将它们添加到您的数据库中。
create index idx_find_player on tblplayer (nameplayer, short, playerid);
create index idx_find_club on tblclub (nameclub, clubid)
create index idx_find_match on tblmatch (date, coach1, coach2, matchid)
create index idx_find_squad1 on tblstartingsquad (matchid, clubid)
create index idx_find_squad2 on tblSsartingsquad (clubid, matchid)
create index idx_find_subs1 on tblsubstitutes (matchid, clubid)
create index idx_find_subs2 on tblsubstitutes (clubid, matchid)
我不确定哪个小队索引更有可能被使用，所以创建两个并查看 DBMS 选择哪个。然后你可以放下另一个。替代索引相同。
为了获得准确的答案，我们必须在 SQL 中查看您的执行计划，将其发送至此处，以便我可以帮助您解决问题
在那之前，我认为你做错了，而不是为单行写一个 select 你可以简单地在你的数据库中定义用户定义的 - table 并传递你的值。通过这样做你可以在你的 SQL 和你的服务器端代码中有更好的性能，我向你保证，你在第一级和之后有最好的性能，正如我之前所说的需要执行计划
- 声明你的类型（不要忘记改变你自己的数据类型）
创建类型 [dbo].[com_ListOfGuid] AS TABLE(NamePlayer NVARCHAR(256) NOT NULL,Short NVARCHAR(256) NOT NULL)
而不是在代码中创建 select 语句，只需声明一个数据 table 并将数据填充到其中并像其他参数一样传递它（不要忘记设置你的列名与你的用户定义的-table-type 完全一样）
3.in 你的 SQL 代码只是加入用户定义的-table-类型和你的 table 并将它们插入你的目标 table （我给你一个例子和你随着你的需要而改变）
创建过程Procedure_Your_Name
@ObjectTable Type_Your_Name 只读
作为
插入 TARGET_Table ()
SELECT
*
从
first_Table F 内连接
@ObjectTable T ON F.NamePlayer = t.NamePlayer 和 t.Short = f.Short
几个月以来，我一直在从公开来源收集足球比赛的数据。为此，我通过 XPath 使用 PHP 获取特定网站 URL 的数据，该网站显示特定足球比赛的数据。然后我进行一些数据编辑，使它们符合我需要的方式。下一步也是最后一步是在 table 秒内将它们传输到我的 MySQL 数据库中。
随着数据库的快速增长，我慢慢地 运行 遇到了严重的性能问题。因为我在我的电脑上本地做所有事情而且那台机器不是怪物，所以处理一场比赛已经需要一些时间。感受一下这有多快：在数据挖掘的最初几天，一场比赛大约需要 24 秒。但是，现在平均值超过了 60 秒的阈值。
到目前为止，我偶尔会研究 PHP 代码并尝试在可能的情况下对其进行改进，因为我认为主要问题在于不太干净的代码片段。虽然它有点帮助，但平均时间在几天后进一步增加，最近我开始意识到必须有另一个耗时的问题。所以我制作了一个测试 PHP 脚本，它在 运行 运行主代码时执行某种日志记录。
它表明我为将数据插入数据库 table 所做的一些 SQL 查询平均花费大量时间（我在这里分析了 100 个匹配项）：
- 数据库中的首发阵容：6.44 秒
- DB 替补队员：8.49 秒
再次检查查询，我发现它们非常复杂。
涉及的 table 个：
tblStartingSquad
+----+---------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+------------+------------+--------+
| id | matchID | player1ID | player2ID | player3ID | player4ID | player5ID | player6ID | player7ID | player8ID | player9ID | player10ID | player11ID | clubID |
+----+---------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+------------+------------+--------+
| 1 | 1 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 1 |
| 2 | 1 | 12 | 13 | 14 | 15 | 16 | 17 | 16 | 17 | 18 | 19 | 20 | 2 |
| 3 | 2 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 1 |
| 4 | 2 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 3 |
+----+---------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+------------+------------+--------+
tblSubstitutes
+----+---------+------------+------------+------------+------------+------------+------------+------------+------------+------------+------------+------------+------------+--------+
| id | matchID | player12ID | player13ID | player14ID | player15ID | player16ID | player17ID | player18ID | player19ID | player20ID | player21ID | player22ID | player23ID | clubID |
+----+---------+------------+------------+------------+------------+------------+------------+------------+------------+------------+------------+------------+------------+--------+
| 1 | 1 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 1 |
| 2 | 1 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 2 |
| 3 | 2 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 1 |
| 4 | 2 | 56 | 57 | 58 | 59 | 60 | 61 | 61 | 62 | 63 | 64 | 65 | 66 | 3 |
+----+---------+------------+------------+------------+------------+------------+------------+------------+------------+------------+------------+------------+------------+--------+
tblMatch
+---------+---------------------+-------------+------------------+
| matchID | date | coach1 | coach2 |
+---------+---------------------+-------------+------------------+
| 1 | 2006-08-19 22:00:00 | Piotr Nowak | Fernando Clavijo |
| 2 | 2006-08-15 21:00:00 | Piotr Nowak | Mustafa Ugur |
+---------+---------------------+-------------+------------------+
tblPlayer
+----------+------------------------+------------------+
| playerID | namePlayer | short |
+----------+------------------------+------------------+
| 1 | Enis Ulusan | enis-ulusan |
| 2 | Grant Robert Murray | grant-murray |
| 3 | Evgeniy Shpedt | evgeniy-shpedt |
| 4 | Mihai Alexandru Costea | mihai-costea |
| 5 | Jan Zolna | jan-zolna |
| 6 | Adrian Gheorghiu | adrian-gheorghiu |
| 7 | Marius Marian Croitoru | marius-croitoru |
| 8 | Jacov Nachtailer | jacov-nachtailer |
| ... | ... | ... |
+----------+------------------------+------------------+
tblClub
+--------+-----------------+
| clubID | nameClub |
+--------+-----------------+
| 1 | D.C. United |
| 2 | Colorado Rapids |
| 3 | Caykur Rizespor |
+--------+-----------------+
这些是涉及的查询：
SQL查询首发阵容
$tblstarting_squad = 'INSERT INTO tblStartingSquad (matchID, player1ID, player2ID, player3ID, player4ID, player5ID, player6ID, player7ID, player8ID, player9ID, player10ID, player11ID, clubID)
SELECT
(SELECT matchID FROM tblMatch WHERE date = "' . $match_date . '" AND coach1 = "' . $match_coach_home . '" AND coach2 = "' . $match_coach_away . '"),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[0] . '" AND short = "' . $player_short[0] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[1] . '" AND short = "' . $player_short[1] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[2] . '" AND short = "' . $player_short[2] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[3] . '" AND short = "' . $player_short[3] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[4] . '" AND short = "' . $player_short[4] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[5] . '" AND short = "' . $player_short[5] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[6] . '" AND short = "' . $player_short[6] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[7] . '" AND short = "' . $player_short[7] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[8] . '" AND short = "' . $player_short[8] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[9] . '" AND short = "' . $player_short[9] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[10] . '" AND short = "' . $player_short[10] . '" LIMIT 1),
(SELECT clubID FROM tblClub WHERE nameClub = "' . $match_club[1] . '" LIMIT 1)
WHERE NOT EXISTS (
SELECT e.matchID
FROM tblStartingSquad As e
INNER JOIN tblMatch As m
ON e.matchID = m.matchID
WHERE m.date = "' . $match_date . '" AND m.coach1 = "' . $match_coach_home . '" AND m.coach2 = "' . $match_coach_away . '" AND e.clubID = (SELECT clubID FROM tblClub WHERE nameClub = "' . $match_club[1] . '")
);';
if (!mysqli_query($db_connection, $tblstarting_squad)) {
echo("Error description $tblstarting_squad: " . mysqli_error($db_connection) . "<br />");
}
SQL 查询替补球员
$tblsubstitutes = 'INSERT INTO tblSubstitutes (matchID, player12ID, player13ID, player14ID, player15ID, player16ID, player17ID, player18ID, player19ID, player20ID, player21ID, player22ID, player23ID, clubID)
SELECT
(SELECT matchID FROM tblMatch WHERE date = "' . $match_date . '" AND coach1 = "' . $match_coach_home . '" AND coach2 = "' . $match_coach_away . '"),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[11] . '" AND short = "' . $player_short[11] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[12] . '" AND short = "' . $player_short[12] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[13] . '" AND short = "' . $player_short[13] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[14] . '" AND short = "' . $player_short[14] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[15] . '" AND short = "' . $player_short[15] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[16] . '" AND short = "' . $player_short[16] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[17] . '" AND short = "' . $player_short[17] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[18] . '" AND short = "' . $player_short[18] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[19] . '" AND short = "' . $player_short[19] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[20] . '" AND short = "' . $player_short[20] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[21] . '" AND short = "' . $player_short[21] . '" LIMIT 1),
(SELECT playerID FROM tblPlayer WHERE namePlayer = "' . $player_name[22] . '" AND short = "' . $player_short[22] . '" LIMIT 1),
(SELECT clubID FROM tblClub WHERE nameClub = "' . $match_club[1] . '" LIMIT 1)
WHERE NOT EXISTS (
SELECT e.matchID
FROM tblSubstitutes As e
INNER JOIN tblMatch As m
ON e.matchID = m.matchID
WHERE m.date = "' . $match_date . '" AND m.coach1 = "' . $match_coach_home . '" AND m.coach2 = "' . $match_coach_away . '" AND e.clubID = (SELECT clubID FROM tblClub WHERE nameClub = "' . $match_club[1] . '")
);';
if (!mysqli_query($db_connection, $tblsubstitutes)) {
echo("Error description $tblsubstitutes: " . mysqli_error($db_connection) . "<br />");
}
这两个查询实际上是相同的。如果没有其他条目具有相同的数据，他们将 11 个（分别为 12 个）玩家的 playerID 插入 tblStartingSquad（分别为 tblSubstitutes）。 playerID 必须事先在数据库中检查，因为原始数据没有个人 ID。通过 namePlayer 和 short 从 table tblPlayer.
tables tblStartingSquad 和 tblSubstitutes 本身目前包含 110,000 行（55,000 个匹配），tblPlayer 是 100,000 行。
我在谷歌上搜索了一些解决方案，但没能找到任何可以提高整体速度的方法。我理解的一个问题是我必须单独检查每个玩家，所以我得到 11 和 12 个子查询。这不是很优雅，但我真的不知道如何改进它。也许 Whosebug 上有人有建议？
正如 O.Jones 在评论中所述，查看更多 (php) 代码有助于判断性能问题。 尽管重新设计了您的数据库，但另一个快速建议实际上是 运行 一个循环并使用 prepared statement 来对玩家 ID 进行单独查询。这可能会给您带来轻微的性能提升。
在我看来确实合乎逻辑，在 PHP 中做更多而不是将数据获取逻辑外包给 SQL。
重新考虑您的 wide table 设计以实现 long table 设计。带编号后缀的列从来都不是理想的数据存储。行很便宜。色谱柱很贵。连接、聚合、搜索、索引等在长格式中要容易得多。否则，您的查询将很复杂，因为您显示有 12 个子查询甚至自连接！
有趣的是，您的 tblClub 和 tblPlayer 是长格式但 tblStartingSquad 和 tblSubstitutes！简单地说，将所有无关的玩家列删除到 one 中，其中行表示不同的玩家：
tblStartingSquad
ID MatchID PlayerID ClubID
1 1 5 1
2 1 8 1
3 1 9 1
...
tblSubstitutes
ID MatchID PlayerID ClubID
1 1 2 1
2 1 16 1
3 1 7 1
...
tblMatch （为清楚起见重命名了教练列）
ID Date HomeCoach AwayCoach
1 2006-08-19 22:00:00 Piotr Nowak Fernando Clavijo
2 2006-08-15 21:00:00 Piotr Nowak Mustafa Ugur
PHP
从这个数据库设计中，您可以 运行 一个更简单的 PHP 参数化查询调用，使用 PDO 更容易，而不是 mysqli 来绑定来自数组。
// OPEN CONNECTION
$dbconn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
// SET PDO ERROR MODE TO EXCEPTION
$dbconn -> setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
// PREPARED STATEMENT
$sql = "INSERT INTO tblStartingSquad (`Match`, `PlayerID`, `ClubID`)
SELECT m.MatchID, p1.PlayerID, c.ClubID
FROM
(SELECT p.PlayerID
FROM tblPlayer p
WHERE p.namePlayer IN (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
) p1
INNER JOIN
(SELECT p.PlayerID
FROM tblPlayer p
WHERE p.short IN (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
) p2 ON p1.PlayerID = p2.PlayerID
CROSS JOIN
(SELECT MatchID
FROM tblMatch
WHERE `date` = ? AND HomeCoach = ? AND AwayCoach = ?) m
CROSS JOIN
(SELECT ClubID
FROM tblClub
WHERE nameClub = ?) c
WHERE NOT EXISTS
(SELECT 1 FROM tblStartingSquad As e
WHERE e.MatchID = m.matchID)"
try {
// INITIALIZE STATEMENT
$stmt = $dbconn->prepare($sql);
$params = array($player_name[0], $player_name[1], $player_name[2],
$player_name[3], $player_name[4], $player_name[5],
$player_name[6], $player_name[7], $player_name[8],
$player_name[9], $player_name[10],
$player_short[0], $player_short[1], $player_short[2],
$player_short[3], $player_short[4], $player_short[5],
$player_short[6], $player_short[7], $player_short[8],
$player_short[9], $player_short[10],
$match_date, $match_coach_home, $match_coach_away, $match_club);
// ITERATIVELY BIND PARAMS
foreach($params as $key => $val) {
$stmt->bindParam($key+1, $val, PDO::PARAM_STR);
}
// EXECUTE ACTION
$stmt->execute();
} catch (PDOException $e) {
echo "Error: " . $e->getMessage();
}
对 tblSubstitutes 进行类似的调用，调整追加查询的目标和 WHERE 子句和参数值。
语句并不复杂。它们只包含大量查找。因此，请确保查找速度很快。您需要以下索引。如果您还没有它们，请将它们添加到您的数据库中。
create index idx_find_player on tblplayer (nameplayer, short, playerid);
create index idx_find_club on tblclub (nameclub, clubid)
create index idx_find_match on tblmatch (date, coach1, coach2, matchid)
create index idx_find_squad1 on tblstartingsquad (matchid, clubid)
create index idx_find_squad2 on tblSsartingsquad (clubid, matchid)
create index idx_find_subs1 on tblsubstitutes (matchid, clubid)
create index idx_find_subs2 on tblsubstitutes (clubid, matchid)
我不确定哪个小队索引更有可能被使用，所以创建两个并查看 DBMS 选择哪个。然后你可以放下另一个。替代索引相同。
为了获得准确的答案，我们必须在 SQL 中查看您的执行计划，将其发送至此处，以便我可以帮助您解决问题
在那之前，我认为你做错了，而不是为单行写一个 select 你可以简单地在你的数据库中定义用户定义的 - table 并传递你的值。通过这样做你可以在你的 SQL 和你的服务器端代码中有更好的性能，我向你保证，你在第一级和之后有最好的性能，正如我之前所说的需要执行计划
- 声明你的类型（不要忘记改变你自己的数据类型）
创建类型 [dbo].[com_ListOfGuid] AS TABLE(NamePlayer NVARCHAR(256) NOT NULL,Short NVARCHAR(256) NOT NULL)
而不是在代码中创建 select 语句，只需声明一个数据 table 并将数据填充到其中并像其他参数一样传递它（不要忘记设置你的列名与你的用户定义的-table-type 完全一样） 3.in 你的 SQL 代码只是加入用户定义的-table-类型和你的 table 并将它们插入你的目标 table （我给你一个例子和你随着你的需要而改变）
创建过程Procedure_Your_Name @ObjectTable Type_Your_Name 只读 作为 插入 TARGET_Table () SELECT * 从 first_Table F 内连接 @ObjectTable T ON F.NamePlayer = t.NamePlayer 和 t.Short = f.Short