Question

我有1个包含所有信息的主表和1个结构几乎相同但值略有不同的表。现在，我想比较这些值并获得最高的差额。我在每个查询（a1-a5）的查询中都使用了此功能，并且在每个查询的循环中我再次查询并使用结果进行一些计算...我不知道，这很杂乱，我不确定如何获得此结果以一种干净的方式。

这是2个表的结构：

+----------+----------+--------+-----+-----+-----+-----+-----+--------------+
| HomeTeam | AwayTeam | Result |  a1 |  a2 |  a3 |  a4 |  a5 |  Date        |
+----------+----------+--------+-----+-----+-----+-----+-----+--------------+
| team1    | team2    |      H |  5  |  2  |  4  |  4  |  3  |  11-04-2017  |
| team3    | team4    |      A |  6  |  8  |  4  |  2  |  6  |  11-04-2017  |
| team1    | team3    |      D |  3  |  7  |  9  |  7  |  2  |  12-04-2017  |
| team4    | team2    |      H |  2  |  4  |  8  |  6  |  5  |  12-04-2017  |
+----------+----------+--------+-----+-----+-----+-----+-----+--------------+

+----------+----------+-----+-----+-----+-----+-----+
| HomeTeam | AwayTeam |  a1 |  a2 |  a3 |  a4 |  a5 |
+----------+----------+-----+-----+-----+-----+-----+
| team1    | team2    |  2  |  3  |  5  |  3  |  3  |
| team3    | team4    |  5  |  7  |  5  |  2  |  3  |
| team1    | team3    |  4  |  2  |  8  |  6  |  5  |
| team4    | team2    |  2  |  5  |  5  |  6  |  4  |
+----------+----------+-----+-----+-----+-----+-----+

这就是我要打印的内容：

team 1 vs team 2 biggest increase was 150% (a1 -> 5 vs 2) on 11-04-2017 
team 3 vs team 4 biggest increase was 100% (a5 -> 6 vs 3) on 11-04-2017 
team 1 vs team 3 biggest increase was 250% (a2 -> 7 vs 2) on 12-04-2017 
team 4 vs team 2 biggest increase was 60% (a3 -> 8 vs 5) on 12-04-2017

当我输入此内容时，我想也许只使用一个查询即可从两个表中获取所有内容，并使用值进行一些计算？不确定。有人可以在正确的方向上给我很大的帮助吗？

Answer 1

我们可以在此处使用GREATEST来查找每次比赛的最大点差：

SELECT
    HomeTeam,
    AwayTeam,
    GREATEST(t1.a1 - t2.a1, t1.a2 - t2.a2, t1.a3 - t2.a3, t1.a4 - t2.a4, t1.a5 - t2.a5) AS max_diff
FROM table1 t1
INNER JOIN table2 t2
    ON t1.HomeTeam = t2.HomeTeam AND t1.AwayTeam = t2.AwayTeam;

如果您还想要实际的a值，那么将需要做更多的工作，尤其是在您的数据未标准化的情况下。您可能希望对数据进行标准化处理，以解决除上述之外的任何复杂工作。

php / mysql-比较2个表格中的多列并显示最大差异

1 个答案: