php - 使用 3 select 向先前的查询添加约束

Question

我有这个查询:

$stmt = $conn->prepare(
    'SELECT * 
    FROM table_shots 
    WHERE idmatch in (
                        select * 
                        from (
                            SELECT mc_id 
                            FROM table_matches 
                            WHERE mc_hometeam = '. $idTeam .' 
                            OR mc_awayteam = '. $idTeam .' 
                            ORDER BY mc_date desc 
                            LIMIT '. $num .'
                            ) temp_tab
                    )'
                );

现在我需要添加另一个条件 table_shots 。

table_shots 也有这个字段:teamtype。该字段可以有两个值:home_team 或 away_team。

现在(在我看来)我们需要的是找到一种方法从第三个 SELECT 中了解 $idTeam 是否在 mc_hometeam 中> 或 mc_awayteam(来自 table_matches)以添加新条件。

新条件将添加到表table_shots(理论上)，如下所示:AND teamtype = home_team(如果 $idTeam code> 位于 table_matches 的 mc_hometeam 中)或 AND teamtype =away_team (如果 $idTeam 位于 table_matches 的 mc_awayteam 中)。

有什么建议吗？

我知道这很难，让我惊讶;)

Answer 1

为什么不使用简单的联接而不是多个选择？

$stmt = $conn->prepare('SELECT ts.* 
    FROM table_shots AS ts 
    JOIN table_matches AS tm ON ts.idmatch = tm.mc_id
    WHERE (mc_hometeam = '. $idTeam .' AND teamtype = 'home_team') OR (mc_awayteam = '. $idTeam .' AND teamtype = 'away_team')
    ORDER BY mc_date desc 
    LIMIT '. $num);

此外，我建议使用 PDO 和参数，而不是将 $idTeam var 连接到查询字符串。

$stmt = $conn->prepare('SELECT ts.* 
    FROM table_shots AS ts 
    JOIN table_matches AS tm ON ts.idmatch = tm.mc_id
    WHERE (mc_hometeam = :idTeam AND teamtype = 'home_team') OR (mc_awayteam = :idTeam AND teamtype = 'away_team')
    ORDER BY mc_date desc 
    LIMIT '. $num);
$stmt->execute([':idTeam' => $idTeam]);

编辑:你是对的，LIMIT 放错了地方。乍一看，将两者结合起来应该可行。

编辑2:下面的第一个查询有效，但在第二个查询中，我将 min() 放在了错误的位置。第三个也有同样的问题。修复了它们。

$stmt = $conn->prepare('SELECT ts.* 
    FROM table_shots AS ts 
    JOIN table_matches AS tm ON ts.idmatch = tm.mc_id
    WHERE ((mc_hometeam = :idTeam AND teamtype = 'home_team') OR (mc_awayteam = :idTeam AND teamtype = 'away_team'))
    AND idmatch in (
                        select * 
                        from (
                            SELECT mc_id 
                            FROM table_matches 
                            WHERE mc_hometeam = :idTeam 
                            OR mc_awayteam = :idTeam 
                            ORDER BY mc_date desc 
                            LIMIT '. $num .'
                            ) temp_tab
                    ));
$stmt->execute([':idTeam' => $idTeam]);

或者这种方法也可以工作，我不确定哪个更好。

$stmt = $conn->prepare('SELECT ts.* 
    FROM table_shots AS ts 
    JOIN table_matches AS tm ON ts.idmatch = tm.mc_id
    WHERE ((mc_hometeam = :idTeam AND teamtype = 'home_team') OR (mc_awayteam = :idTeam AND teamtype = 'away_team'))
    AND mc_date >= (
                        SELECT min(mc_date)
                        FROM (
                            SELECT mc_date
                            FROM table_matches 
                            WHERE mc_hometeam = :idTeam 
                            OR mc_awayteam = :idTeam 
                            ORDER BY mc_date desc 
                            LIMIT '. $num .'
                            ) temp_tab
                    ));
$stmt->execute([':idTeam' => $idTeam]);

或者，当然您可以在单独的查询中获取 minDate。我认为这更具可读性。

$stmt = $conn->prepare('SELECT min(mc_date)
                        FROM (
                            SELECT mc_date
                            FROM table_matches 
                            WHERE mc_hometeam = :idTeam 
                            OR mc_awayteam = :idTeam 
                            ORDER BY mc_date desc 
                            LIMIT '. $num .'
                            ) temp_tab);
$stmt->execute([':idTeam' => $idTeam]);
$result = $stmt->fetch(\PDO::FETCH_ASSOC);

$stmt = $conn->prepare('SELECT ts.* 
    FROM table_shots AS ts 
    JOIN table_matches AS tm ON ts.idmatch = tm.mc_id
    WHERE ((mc_hometeam = :idTeam AND teamtype = 'home_team') OR (mc_awayteam = :idTeam AND teamtype = 'away_team'))
    AND mc_date >= :minDate');

$stmt->execute([':idTeam' => $idTeam, ':minDate' => $result['minDate']]);