SQLITE:显示每个类别的总计(总和)

Question

我有两个表(输入和类别):

CREATE TABLE categories (
    iId INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
    sName TEXT NOT NULL,
    iParent INTEGER,
    FOREIGN KEY (iParent) REFERENCES categories(iId)
);

CREATE TABLE inputs (
    iId INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
    iCategory INTEGER,
    dValue DOUBLE NOT NULL,
    FOREIGN KEY (iCategory) REFERENCES categories(iId)
);

我需要从每个类别的输入表中获取总和(dValue 列)。即使总和结果为零。

如果我能得到每个父类别的总和(当 categories.iId = categories.iParent 时，将子类别的结果加到父类别中)是否可能会更好

谁能帮帮我？感谢您的帮助!谢谢!

Answer 1

试试这个:

select c.iParent, sum(i.dValue)
from categories c
left outer join inputs i on i.iCategory=c.iId
group by c.iParent

编辑:使用帐户:

select c.iParent, a.iCurrency, sum(i.dValue)
from categories c
left outer join inputs i on i.iCategory=c.iId
left outer join accounts a on i.iAccount=a.iId
group by c.iParent,a.iCurrency