Question

我正在iReport中创建一个报告。我正在使用postgresql9.2数据库。尝试基于另一个字段创建求和。首先，我按车辆编号逐个字段创建报表，然后创建一个变量，尝试在此字段中按组逐个求和。

我的报告结果

vh_name    |  va_date   | trip_no |
Vehicle-01 | 2019-01-15 |   1     |
Vehicle-01 | 2019-01-15 |   1     |
Vehicle-01 | 2019-01-16 |   1     |
-----------+------------+---------+
Vehicle-02 | 2019-01-17 |   1     |
Vehicle-02 | 2019-01-18 |   1     |
Vehicle-02 | 2019-01-19 |   1     |
-----------+------------+---------+
Vehicle-03 | 2019-01-17 |   1     |
Vehicle-03 | 2019-01-17 |   1     |
Vehicle-03 | 2019-01-17 |   1     |
Vehicle-03 | 2019-01-18 |   1     |
-----------+------------+---------+

我的预期结果

vh_name    |  va_date   | trip_no | total_trip |
Vehicle-01 | 2019-01-15 |   1     |            |
Vehicle-01 | 2019-01-15 |   1     |     3      |
Vehicle-01 | 2019-01-16 |   1     |            |
-----------+------------+---------+-------------
Vehicle-02 | 2019-01-17 |   1     |            |
Vehicle-02 | 2019-01-18 |   1     |     3      |
Vehicle-02 | 2019-01-19 |   1     |            |
-----------+------------+---------+-------------
Vehicle-03 | 2019-01-17 |   1     |            |
Vehicle-03 | 2019-01-17 |   1     |            |
Vehicle-03 | 2019-01-17 |   1     |      4     |
Vehicle-03 | 2019-01-18 |   1     |            |
-----------+------------+---------+-------------

Answer 1

基于Using SUM() without grouping the results，您的SQL应该看起来像这样：

SELECT vh_name, va_dat, trip_no, SUM(trip_sum.amount) as trip_sum
FROM my_trips
CROSS JOIN (
    SELECT SUM(amount) as amount FROM my_trips AS amount
    GROUP BY vh_name) trip_sum

请注意，唯一计数可能更容易（如果trip_no始终为1）：

SELECT vh_name, va_dat, trip_no, COUNT(DISTINCT vh_name) as amount
FROM my_trips

基于另一个字段的一个字段的求和

1 个答案: