麻烦sql列

Question

我在数据库（MS Access）（水果和蔬菜）中有2个表。它们中的每一个都有“Date”和“Value”字段。可以有几行具有相同的日期。 如何输出一个表格，该表格将显示每行“日期”，“水果价值总和”和“Vgetables的价值总和”？并且，例如，如果某些“日期”的“蔬菜”没有“值”，那么空单元格会出现吗？

Example is on the screenshot

Answer 1

尝试这样的事情（未经测试）：

SELECT t.date, SUM(f_val) as f_val, SUM(v_val) AS v_val
FROM (
    SELECT date, value AS f_val, 0 AS v_val FROM Fruits 
    UNION ALL
    SELECT date, 0, value FROM Vegetables
) t
GROUP BY t.date

Answer 2

SELECT Date,Sum(fValue) as FruitsValue,Sum(vValue) as VegtablesValue
FROM
(
SELECT Date,value as fValue,null as vValue FROM Fruits 
UNION ALL SELECT Date,null as fValue,Value as vValue  FROM Vegetables
) T
GROUP BY Date