Question

我不是SQL专业人员，所以也许我正在使事情复杂化，但这就是问题所在。我的商店系统有5张桌子。

商品表保存有关店内所有物品的信息。

create table goods(
    id int unsigned not null auto_increment,
    name varchar(255) not null,
    code varchar(20) not null unique,
    sellingPrice float,
    primary key(id)
);

收据表保存有关购买的信息。

create table receipt(
    id int unsigned not null auto_increment,
    company varchar(255) not null,
    identifier varchar(50) unique,
    date date not null,
    price float not null,
    primary key(id)
);

issue_card 表保存有关购买的信息。

create table issue_card(
    id int unsigned not null auto_increment,
    identifier varchar(50) unique,
    receiver varchar(255),
    date date not null,
    primary key(id)
);

商品和收据表已连接（一次购买了多个商品）

create table goods_receipt (
    goods_id int unsigned not null,
    receipt_id int unsigned not null,
    amount int unsigned not null,
    inp_price float not null,
    foreign key (goods_id) references goods(id),
    foreign key (receipt_id) references receipt(id),
    CONSTRAINT goods_receipt_unique UNIQUE (goods_id, receipt_id)
);

商品和 issue_card 已连接（一次售出多种商品）

create table issue_card_goods (
    goods_id int unsigned not null,
    issue_card_id int unsigned not null,
    amount int unsigned not null,
    foreign key (goods_id) references goods(id),
    foreign key (issue_card_id) references issue_card(id),
    CONSTRAINT goods_receipt_unique UNIQUE (goods_id, issue_card_id)
);

我需要找出的是在给定时间分别存储的每个项目的总金额。

示例： 2015年1月4日-商店里有100个橘子（到那天可能买了100,000个，卖了99,900个），还有1000个香蕉，...

到目前为止，我设法做到的是：

通过创建此视图来获得以上结果（计数所有项目，但没有时间限制）

CREATE VIEW store_items 
AS 
  SELECT main.id, 
         main.NAME, 
         main.code, 
         Ifnull(main.bought, 0) - Ifnull(sec.sold, 0) AS available, 
         main.sellingprice 
  FROM   (SELECT goods.id, 
                 goods.NAME, 
                 goods.code, 
                 Sum(goods_receipt.amount) AS bought, 
                 goods.sellingprice 
          FROM   goods 
                 LEFT JOIN goods_receipt 
                        ON goods.id = goods_receipt.goods_id 
          GROUP  BY code) AS main 
         JOIN (SELECT goods.code, 
                      Sum(issue_card_goods.amount) AS sold 
               FROM   goods 
                      LEFT JOIN issue_card_goods 
                             ON goods.id = issue_card_goods.goods_id 
               GROUP  BY code) AS sec 
           ON main.code = sec.code;

考虑到时间限制，我创建了2个视图。在第一个中，我将收据与货物合并在一起。

CREATE VIEW store_items_sold_date 
AS 
  SELECT goods.id    AS id, 
         goods.code  AS code, 
         goods.NAME  AS NAME, 
         giss.amount AS amount, 
         giss.date   AS date_sold 
  FROM   (SELECT * 
          FROM   issue_card 
                 LEFT JOIN issue_card_goods 
                        ON issue_card.id = issue_card_goods.issue_card_id) AS 
         giss 
         LEFT JOIN goods 
                ON giss.goods_id = goods.id;

哪个给我日期和售出的每个物品的数量。

第二个视图类似，仅用于购买（将issue_card与商品一起使用）

CREATE VIEW store_items_bought_date 
AS 
  SELECT goods.id   AS id, 
         goods.code AS code, 
         goods.NAME AS NAME, 
         gr.amount  AS amount, 
         gr.date    AS date_bought 
  FROM   (SELECT * 
          FROM   receipt 
                 LEFT JOIN goods_receipt 
                        ON receipt.id = goods_receipt.receipt_id) AS gr 
         LEFT JOIN goods 
                ON gr.goods_id = goods.id;

现在，我可以获得每个商品的总销售量和购买量。

SELECT id, 
       code, 
       NAME, 
       Sum(amount) AS bought 
FROM   store_items_bought_date 
WHERE  date_bought < "2015-04-05" 
GROUP  BY id;

和

SELECT id, 
       code, 
       NAME, 
       Sum(amount) AS sold 
FROM   store_items_sold_date 
WHERE  date_sold < "2015-04-05" 
GROUP  BY id;

我所缺少的是如何将这些结果结合在一起。我在这里找到了这个查询

(SELECT ... FROM tbl1 LEFT JOIN tbl2 ...) UNION ALL (SELECT ... FROM tbl1 RIGHT JOIN tbl2 ... WHERE tbl1.col IS NULL)

但是我未能将其映射到上述结果，问题是在tbl2处使用了SELECT语句而不是表。任何帮助，将不胜感激。

SELECT语句的MySQL连接结果

0 个答案: