Question

<!-- language: lang-none -->
+----------------------------------------+
|        Here is my sample table         |
+----------------------------------------+
| Date       Person    Column_1    Column_2 |
| 15-03-13    A       100         NULL   |
| 15-03-13    B       NULL         100   |
| 16-03-13    A       100           50   |
| 16-03-13    B       NULL         NULL  |
| 17-03-13    A       100           50   |
| 17-03-13    B       20            30   |
+----------------------------------------+

现在我想按日期做总和（column_1）。但我还需要哪一行包含NULL数据。这是我想要实现的输出结果

+---------------------------------+
| Date       SUM  includesNullval |
+---------------------------------+
| 15-03-13   100   true           |
| 16-03-13   100   true           |
| 17-03-13   120   false          |
+---------------------------------+

我不知道要达到以上输出。任何人都可以给我任何想法或解决这个问题吗？

Answer 1

使用案例陈述可以帮助您：

Select Date_Column, sum(column_A), 
MAX(CASE when column_A is NULL then 'True' else 'False' end) "Includes_NULL_Value"
from table_x
group by Date_column;

REX TESTER

Answer 2

请注意答案的形式和内容。

DROP TABLE IF EXISTS my_table;

CREATE TABLE my_table
(date DATE NOT NULL
,person CHAR(1) NOT NULL
,column_1 INT NULL
,column_2 INT NULL
,PRIMARY KEY(date,person)
);

INSERT INTO my_table VALUES
('2013-03-15','A', 100, NULL),
('2013-03-15','B',NULL,  100),
('2013-03-16','A', 100,   50),
('2013-03-16','B',NULL, NULL),
('2013-03-17','A', 100,   50),
('2013-03-17','B',  20,   30);

SELECT date, SUM(column_1), MAX(column_2 IS NULL) incnull FROM my_table GROUP BY date;
+------------+---------------+---------+
| date       | SUM(column_1) | incnull |
+------------+---------------+---------+
| 2013-03-15 |           100 |       1 |
| 2013-03-16 |           100 |       1 |
| 2013-03-17 |           120 |       0 |
+------------+---------------+---------+

如何获取列的部分总和并找到哪些行在mysql

2 个答案: