如果列名包含且值等于MYSQL，则选择计数

Question

这是我的表格呼叫TrainingPresence

+-------+-----------+-----------+-----------+
| Name  | FootNov12 | HandNov15 | FootNov22 |
+-------+-----------+-----------+-----------+
| Clem  | x         | Abs       | Abs       |
+-------+-----------+-----------+-----------+
| Kevin | x         | x         | x         |
+-------+-----------+-----------+-----------+

我想选择球员参加足部训练的名称和时间。

FootNov12 = Football Novembrre 12th
FootNov22 = Football November 22th
HandNov15 = Handball November 15th

select查询应该给我：

Name | Count
Clem |  1
Kevin|  2

但是我不知道该怎么做 感谢您的帮助。

Answer 1

标准化的架构可能看起来像这样

users
user_id name
1       Clem
2       Kevin

training
user_id date       sport 
      1 2018-11-15 Handball
      1 2018-11-11 Football