我如何计算和汇总数据库中的值

Question

我在mysql中有一个表，它以整数形式保存值，我的表是这样的。

我想总结某个特定列的值，例如我想计算总金额，现金支付总额和总余额。我能做到吗？

Answer 1

使用MySQL的SUM()功能：

select SUM(amount) from tablename;
select SUM(cashpaid) from tablename;
select SUM(balance) from tablename;

或者您可以将它们分组为一个：

select SUM(amount), SUM(cashpaid), SUM(balance) from tablename;

Answer 2

如果您想在一个查询中执行此操作：

SELECT SUM(amount) as total_amount, SUM(cashpaid) as total_paid,SUM(balance) as total_balance FROM tablename;

计算元素使用COUNT（）

SELECT COUNT(*) FROM tablename;

使用此函数时，最好为列名使用别名。

Answer 3

试试这个：

select SUM(amount) AS total_amount, SUM(cashpaid) AS total_cashpaid, SUM(balance) AS total_balance  from tablename;

Answer 4

试

select sum(amount), sum(cashpaid), sum(balance) from tablename

Answer 5

使用count()函数计算记录总数。

像：

select count(amount) from table_name;

它将从您问题3中的上表返回。

用于SUM()查询中的总和SELECT。 像：

select SUM(amount) as total_amount,SUM(cashpaid) as total_cash_paid,SUM(balance) as total_balance from table_name;

<{1>之后as是您的新列名，它将在执行查询后自动创建。