我知道它是重复的,但我很困惑。我不擅长数据库。
我知道可以通过代码轻松处理它。但请求是为了查询,这就是我要走这条路的原因。
我通过此查询获得了如下数据
**SELECT c.CASE_NUMBER,mt.MAIN_TEST_NAME, t.TASK_START, t.TASK_END FROM `CASE` c
INNER JOIN MAIN_TEST mt ON c.CASE_ID=mt.CASE_ID
INNER JOIN JOB j on c.CASE_ID = j.JOB_ID
INNER JOIN TASK t on j.TASK_ID= t.TASK_ID
WHERE (c.CREATION_DATE BETWEEN '2019-01-01 00:00:00' AND CURDATE() )**
CASE NUMBER MAIN TEST TASK_START TASK_END
09232 BX 11/8/2019 14:40 11/8/2019 15:40
09232 FH 11/8/2019 13:35 11/8/2019 15:12
09234 FH 11/6/2019 12:54 11/6/2019 14:54
09234 BX 11/6/2019 11:23 11/6/2019 13:44
我尝试了以下查询,
**SELECT c.CASE_NUMBER,
(CASE WHEN mt.MAIN_TEST_NAME='BX' THEN t.TASK_START END) as 'BX_START_DATE',
(CASE WHEN mt.MAIN_TEST_NAME='FH' THEN t.TASK_START END) as 'FH_START_DATE'
FROM `CASE` c
INNER JOIN MAIN_TEST mt ON c.CASE_ID=mt.CASE_ID
INNER JOIN JOB j on c.CASE_ID = j.JOB_ID
INNER JOIN TASK t on j.TASK_ID= t.TASK_ID
WHERE (c.CREATION_DATE BETWEEN '2019-01-01 00:00:00' AND CURDATE() )**
但是在这个查询中,我对如何在条件为真时创建 TASK_END 列感到困惑。
我想要这种格式的数据。
CASE NUMBER BX_TASK_START BX_TASK_END FH_TASK_START FH_TASK_END
09232 11/8/2019 14:40 11/8/2019 15:40 11/8/2019 13:35 11/8/2019 15:12
09234 11/6/2019 11:23 11/6/2019 13:44 11/6/2019 12:54 11/6/2019 14:54
最佳答案
您必须聚合这些 case 表达式:
SELECT c.CASE_NUMBER,
MAX(CASE WHEN mt.MAIN_TEST_NAME='BX' THEN t.TASK_START END) as 'BX_TASK_START',
MAX(CASE WHEN mt.MAIN_TEST_NAME='BX' THEN t.TASK_END END) as 'BX_TASK_END',
MAX(CASE WHEN mt.MAIN_TEST_NAME='FH' THEN t.TASK_START END) as 'FH_TASK_START',
MAX(CASE WHEN mt.MAIN_TEST_NAME='FH' THEN t.TASK_END END) as 'FH_TASK_END'
FROM `CASE` c
INNER JOIN MAIN_TEST mt ON c.CASE_ID=mt.CASE_ID
INNER JOIN JOB j on c.CASE_ID = j.JOB_ID
INNER JOIN TASK t on j.TASK_ID= t.TASK_ID
WHERE (c.CREATION_DATE BETWEEN '2019-01-01 00:00:00' AND CURDATE())
GROUP BY c.CASE_NUMBER
关于mysql - 如何根据值将多行转换为多列,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/59466289/