MySQL 5.5-每天计算未结项目

Question

我有一张下表只是一个快照，我要做的就是计算每个日期未清项目的数量。

我曾经在Excel中使用简单的公式=COUNTIFS($A$2:$A$30000,"<="&E2,$B$2:$B$30000,">="&E2)进行操作，其中A列是Open_Date日期，B列是Close_Date日期。我想使用SQL来获得相同的结果。

这是我的excel快照。上面的公式。

在mysql中，我已使用T1表将其复制：

CREATE TABLE T1
(

ID int (10),
Open_Date date,
Close_Date date);


insert into T1 values (1, '2018-12-17', '2018-12-18');
insert into T1 values (2, '2018-12-18', '2018-12-18');
insert into T1 values (3, '2018-12-18', '2018-12-18');
insert into T1 values (4, '2018-12-19', '2018-12-20');
insert into T1 values (5, '2018-12-19', '2018-12-21');
insert into T1 values (6, '2018-12-20', '2018-12-22');
insert into T1 values (7, '2018-12-20', '2018-12-22');
insert into T1 values (8, '2018-12-21', '2018-12-25');
insert into T1 values (9, '2018-12-22', '2018-12-26');
insert into T1 values (10, '2018-12-23', '2018-12-27');

第一步是创建带有日期的表，以防Date_open中有任何间隙。因此，目前我的代码是

SELECT
    d.dt, Temp_T1.*
FROM
(
    SELECT '2018-12-17' AS dt UNION ALL
    SELECT '2018-12-18' UNION ALL
    SELECT '2018-12-19' UNION ALL
    SELECT '2018-12-20' UNION ALL
    SELECT '2018-12-21' UNION ALL
    SELECT '2018-12-22' UNION ALL
    SELECT '2018-12-23' UNION ALL
    SELECT '2018-12-24'
) d

LEFT JOIN 
(SELECT * FROM T1) AS Temp_T1
ON Temp_T1.Open_Date = d.dt

我不知道如何计算与excel中相同的值？

Answer 1

您要使用GROUP BY为d派生表中的每个日期创建一行。

然后将d连接到t1表，其中d.dt在打开日期和关闭日期之间。

SELECT
    d.dt, COUNT(*) AS open_items
FROM
(
    SELECT '2018-12-17' AS dt UNION ALL
    SELECT '2018-12-18' UNION ALL
    SELECT '2018-12-19' UNION ALL
    SELECT '2018-12-20' UNION ALL
    SELECT '2018-12-21' UNION ALL
    SELECT '2018-12-22' UNION ALL
    SELECT '2018-12-23' UNION ALL
    SELECT '2018-12-24'
) d
LEFT JOIN T1 ON d.dt BETWEEN t1.Open_Date and t1.Close_Date
GROUP BY d.dt;

输出：

+------------+------------+
| dt         | open_items |
+------------+------------+
| 2018-12-17 |          1 |
| 2018-12-18 |          3 |
| 2018-12-19 |          2 |
| 2018-12-20 |          4 |
| 2018-12-21 |          4 |
| 2018-12-22 |          4 |
| 2018-12-23 |          3 |
| 2018-12-24 |          3 |
+------------+------------+