Question

我需要显示存储在MySQL数据库表中的数据摘要

control_point_run

run_date    control_point   duration
10/10/2016  A   100
10/10/2016  B   200
10/10/2016  C   150
10/11/2016  A   160
10/11/2016  B   220
10/11/2016  C   180
10/12/2016  A   200
10/12/2016  B   120
10/12/2016  C   180

预期产出

run_date    A   B   C
10/10/2016  100 200 150
10/11/2016  160 220 180
10/12/2016  200 120 180

Requirement image 请帮我MySQL查询以获得预期的结果。我不知道如何将行数据转换为列标题[A，B，C]。

请注意，需要根据可用数据自动生成预期的列名（A，B，C）。该表包含的数据多于此示例中的数据，并且以后还可以插入更多的control_point值。

Answer 1

使用透视查询：

SELECT run_date,
       MAX(CASE WHEN control_point = 'A' THEN duration END) AS A,
       MAX(CASE WHEN control_point = 'B' THEN duration END) AS B,
       MAX(CASE WHEN control_point = 'C' THEN duration END) AS C
FROM yourTable
GROUP BY run_date

Answer 2

这可能是对的。请检查一下：

 SELECT run_date,
   (SELECT duration from tablename where control_point = 'A') as 'A',
   (SELECT duration from tablename where control_point = 'B') as 'B',
   (SELECT duration from tablename where control_point = 'C') as 'C' 
 FROM tablename
 GROUP BY run_date;

Mysql Query将行数据显示为列

2 个答案: