mysql - MariaDB 查询问题(忽略 ORDER BY)

Question

我有一个运行良好的 MySQL 查询，但我的托管提供商将我的数据库更改为 MariaDB。查询本身工作正常，但我无法像在 MySQL 中那样使排序正常工作。

是否有某些语法已更改或不再可用？

    SELECT
 id,
  name,
  position,
  player1,
  player1_thru,
  player1_to_par,
  player2,
  player2_thru,
  player2_to_par,
  player3,
  player3_thru,
  player3_to_par,
  team_total,
  IF (counter = 1, @rank:= placeholder, @rank) AS ranker
FROM(
  SELECT
    *,
    @c := @c +1 AS placeholder,
    IF(@a <> team_total, @b := @b := 1, @b :=0) AS counter,
    @a := team_total
  from(
    SELECT
        usopen_2018.id,
        usopen_2018.position
        , usopen_2018.name
       , usopen_2018.player1
       , player1_score.hole as player1_thru
       , player1_score.to_par_s AS player1_to_par
       , usopen_2018.player2
       , player2_score.hole as player2_thru
       , player2_score.to_par_s AS player2_to_par
       , usopen_2018.player3
       , player3_score.hole as player3_thru
       , player3_score.to_par_s AS player3_to_par
       , (player1_score.`to_par` + player2_score.`to_par` + player3_score.`to_par`) AS team_total
    FROM usopen_2018
    INNER JOIN leaderboard_A AS player1_score
      ON player1_score.name = usopen_2018.player1
      AND player1_score.tournament_name = 'U.S. Open'
      AND player1_score.year = 2018
    INNER JOIN leaderboard_A AS player2_score
      ON player2_score.name = usopen_2018.player2
      AND player2_score.tournament_name = 'U.S. Open'
      AND player2_score.year = 2018
    INNER JOIN leaderboard_A AS player3_score
      ON player3_score.name = usopen_2018.player3
      AND player3_score.tournament_name = 'U.S. Open'
      AND player3_score.year = 2018
    WHERE usopen_2018.cut = 0 AND usopen_2018.wd = 0
    ORDER BY team_total, player1, player2, player3, name
  )AS t
)AS FINAL

Answer 1

ORDER BY 需要移出一层。

原因如下。 MariaDB 现在 遵守该标准，该标准表示子选择是一组无序行。也就是说，可以忽略内部 ORDER BY。 MariaDB 在最近的几个版本中已经这样做了； MySQL 在最新版本中也是这样做的。

过去，MySQL 和 MariaDB 盲目地执行用户请求的任何 ORDER BY。然后将结果按顺序提供给查询的下一阶段。

LIMIT 技巧

如果这不起作用，请在最里面的 SELECT 中的 ORDER BY 之后添加 LIMIT 99999999。这应该可以防止优化器忽略 ORDER BY，而实际上并未执行任何“限制”。