用连接求和所有行

Question

如何使用连接对查询中的所有行求和？

SELECT SUM(accounting.amount) AS sum, SUM(balance_invoice.amount) AS sum_balance
FROM accounting
LEFT JOIN balance_invoice ON balance_invoice.accounting_id=accounting.id

我需要此查询只返回一行，总和为accounting.amount和balance_invoice.amount

可以将多行连接到每个accounting.id

更新

SELECT SUM(accounting.currency_amount*-1 + (
    SELECT SUM(balance_invoice_accounting.currency_amountoff)
    FROM balance_invoice_accounting
    WHERE balance_invoice_accounting.accounting_id=accounting.id
)) AS sum
FROM accounting

Answer 1

只需在SUM() - 函数中添加两个值：

SELECT SUM(accounting.amount + balance_invoice.amount) AS sum_all
FROM accounting
LEFT JOIN balance_invoice ON balance_invoice.accounting_id=accounting.id

如果其中一列可以是NULL，则应添加其他COALESCE()：

SELECT
SUM(COALESCE(accounting.amount,0) + COALESCE(balance_invoice.amount,0) AS sum_all
FROM accounting
LEFT JOIN balance_invoice ON balance_invoice.accounting_id=accounting.id

修改
对不起，我错过了那个重要的部分。如果您只想计算每accounting.amount个balance_invoice.amount，而且可以有多个SELECT a.id, ( a.amount + (SELECT SUM(b.amount) FROM balance_invoice b WHERE b.accounting_id = a.id) ) AS sum_all FROM accounting a 加入它，我会使用这样的子选择：

{{1}}