在mysql视图中计算每个产品的运行平衡

我在mysql中有一个视图（

vwbalance

），我用它来检查商店中我们产品的当前库存余额，它在一个产品上运行得非常好。 这里是风景

CREATE VIEW vwbalance AS
SELECT
  a.`id`      AS `Trans No`,
  a.`tdate` AS Siku,
  a.`section` AS `Section`,
  `g`.`p_name` AS `Product`,
  a.`cr`      AS `In`,
  a.`dr`      AS `Out`,
  SUM((o.`cr` - o.`dr`)) AS `balance`,
  a.`status`  AS `status`
FROM ((`trn_inventory` a
    LEFT JOIN `mst_product` `g`
      ON ((`g`.`p_id` = a.`p_id`)))
   JOIN `trn_inventory` o
     ON (((a.`tdate` > o.`tdate`)
           OR ((a.`tdate` = o.`tdate`)
               AND (a.`id` >= o.`id`)))))
WHERE (o.`status` = 'APPROVED')
GROUP BY a.`tdate` DESC,a.`id` DESC;

上述视图从两个表中获取数据，一个是存储所有库存交易（进出产品）的

trn_inventory

，另一个是存储产品详细信息的

mst_product

。我们创建此视图的主要原因基本上是显示运行余额，因为表trn\U库存不存储余额，下面是表定义

CREATE TABLE trn_inventory (
  id INT(25) NOT NULL AUTO_INCREMENT,
  tdate DATE NOT NULL,
   p_id INT(25) NOT NULL,
   dr INT(5) DEFAULT '0' COMMENT 'OUT',
  cr INT(5) DEFAULT '0' COMMENT 'IN',
  cost DOUBLE(13,2) NOT NULL DEFAULT '0.00',
  section VARCHAR(95) DEFAULT NULL,
  ref VARCHAR(95) DEFAULT NULL,
  trans_user VARCHAR(35) NOT NULL,
  `status` ENUM('PENDING','APPROVED','DISPATCHED','VOID') NOT NULL DEFAULT 'PENDING',
  approvedby VARCHAR(35) DEFAULT NULL,
  dispatchedby VARCHAR(35) DEFAULT NULL,
  PRIMARY KEY (id)
) ENGINE=INNODB DEFAULT CHARSET=latin1;

这是我从vwbalance运行

SELECT*时的输出：

Trans  Siku      Section   Product         In   Out  Bal  Status  
-------------------------------------------------------------------
8   2014-02-05  "Store"   "Treated SEEDS"   0   10   68  "APPROVED"
7   2014-02-05  "Store"   "Treated SEEDS"  50    0   78  "APPROVED"
5   2014-02-04  "Store"   "Dry Seeds"      40    0   28  "APPROVED"
3   2014-01-16  "Store"   "Dry Seeds"       0    2  -12  "APPROVED"
4   2014-01-15  "Store"   "Dry Seeds"       0   15  -10  "APPROVED"
2   2014-01-15  "Store"   "Dry Seeds"      10    0    5      "VOID"
1   2014-01-15  "store"   "Dry Seeds"      12    0    5  "APPROVED"
6   2014-01-14  "Store"   "Dry Seeds"       0    7   -7  "APPROVED"

我希望它显示每个产品的余额：

Trans  Siku      Section   Product         In   Out  Bal  Status  
-------------------------------------------------------------------
8   2014-02-05  "Store"   "Treated SEEDS"   0   10   40  "APPROVED"
7   2014-02-05  "Store"   "Treated SEEDS"  50    0   50  "APPROVED"
5   2014-02-04  "Store"   "Dry Seeds"      40    0   28  "APPROVED"
3   2014-01-16  "Store"   "Dry Seeds"       0    2  -12  "APPROVED"
4   2014-01-15  "Store"   "Dry Seeds"       0   15  -10  "APPROVED"
2   2014-01-15  "Store"   "Dry Seeds"      10    0    5      "VOID"
1   2014-01-15  "store"   "Dry Seeds"      12    0    5  "APPROVED"
6   2014-01-14  "Store"   "Dry Seeds"       0    7   -7  "APPROVED"

我修改了分组

...
...
 WHERE (o.`status` = 'APPROVED')
    GROUP BY a.`tdate` DESC,a.`id` DESC,o.p_id;

但是它返回了两行，下面的第二个产品是输出

Trans  Siku      Section   Product         In   Out  Bal  Status  
-------------------------------------------------------------------
 8  2014-02-05  "Store"   "Treated SEEDS"   0   10   28  "APPROVED"
 8  2014-02-05  "Store"   "Treated SEEDS"   0   10   40  "APPROVED"
 7  2014-02-05  "Store"   "Treated SEEDS"  50    0   28  "APPROVED"
 7  2014-02-05  "Store"   "Treated SEEDS"  50    0   50  "APPROVED"
 5  2014-02-04  "Store"   "Dry Seeds"      40    0   28  "APPROVED"
 3  2014-01-16  "Store"   "Dry Seeds"       0    2  -12  "APPROVED"
 4  2014-01-15  "Store"   "Dry Seeds"       0   15  -10  "APPROVED"
 2  2014-01-15  "Store"   "Dry Seeds"      10    0    5      "VOID"
 1  2014-01-15  "store"   "Dry Seeds"      12    0    5  "APPROVED"
 6  2014-01-14  "Store"   "Dry Seeds"       0    7   -7  "APPROVED"

我哪里做错了

我已经创建了一个示例，您可以在其中使用示例数据获取此模式，您可以在其中测试查询
您在创建视图中没有匹配两个表的产品id。
因此，您需要如下设置您的条件

 WHERE (o.status = 'APPROVED' and o.p_id = a.p_id)
GROUP BY a.`tdate` DESC,a.`id` DESC,o.p_id;

请参见“工作”
您正在按日期选择和加入，但按日期分组？我已更正了键入错误更正后结果是否会更改？更正是键入错误，但视图本身没有键入错误。还是没有变化，有什么建议吗？