我该如何修复这个查询 - Mysql

Question

我的查询有点问题，这是我的表：

CREATE TABLE IF NOT EXISTS `realizado` (
`cod` int(11) NOT NULL AUTO_INCREMENT,
`datedoc` date NOT NULL,
`bank` int(11) NOT NULL,
`bankValue` float NOT NULL,
PRIMARY KEY (`cod`));

INSERT INTO `realizado` (`cod`, `datedoc`, `bank`, `bankValue`) VALUES
(152, '2014-10-22', 22, 1000),
(153, '2014-10-22', 23, 2000),
(154, '2014-10-22', 24, 3000),
(200, '2014-10-23', 22, 950),
(201, '2014-10-25', 22, 100),
(202, '2014-10-25', 23, 2050),
(203, '2014-10-24', 22, 150),
(204, '2014-10-24', 24, 3800);

问题是：我需要从日期开始 bankValue ，然后按银行分组，如下所示：

SELECT bank, bankValue
FROM realizado
WHERE datedoc <= '2014/10/25'
GROUP BY bank

我最接近的是：

SELECT r.bank, (select bankValue from realizado r2 where max(r.cod) = r2.cod) as Value
FROM realizado as r
WHERE r.datedoc <= '2014/10/25'
GROUP BY r.bank

如果你愿意，这里是SQL小提琴 - ＆gt; http://sqlfiddle.com/#!2/83e309/2

我期望的结果是（ 22 - 100 / 23 - 2050 / 24 - 3800）

Answer 1

您似乎想要银行的最新价值。如果是这样，你可以这样做：

select r.*
from realizado r
where not exists (select 1 from realizao r2 where r2.bank = r.bank and r2.datedoc > r.datedoc);

Answer 2

你走了！ （感谢您使用DDL和bootstrap数据设置sqlFiddle：）

使用sqlFiddle：http://sqlfiddle.com/#!2/83e309/10

SELECT  a.*
FROM    realizado a
        INNER JOIN
        (
            SELECT  bank, MAX(datedoc) datedoc
            FROM    realizado
            GROUP   BY bank
        ) b ON a.bank = b.bank AND
                a.datedoc = b.datedoc