Question

我有一张包含股票交易的表格：

+------+----------------------+------------------+
| Item | Running Stock Total  | Transaction Time |
+------+----------------------+------------------+
| foo  | 4                    | 2012-05-12 11:07 |
| bar  | 3                    | 2012-05-12 10:42 |
| bar  | 3                    | 2012-05-12 9:42  |
| bar  | 2                    | 2012-05-11 15:42 |
| foo  | 3                    | 2012-05-11 10:02 |
| bar  | 3                    | 2012-05-10 13:44 |
...etc...
+------+----------------------+------------------+

即。任何时候发生库存事件，在此表中创建一行 - 这可能意味着库存水平上升（订购新库存），下降（库存销售）或保持不变（库存重新定位）。

我需要创建一个sql查询，该查询只返回特定部分的库存水平实际已更改的行，并且需要在“库存增加”和“库存减少”列中显示更改。

即。 1 Item='bar'

+------+-----------+------------+----------------------+------------------+
| Item | Stock Up  | Stock Down | Running Stock Total  | Transaction Time |
+------+-----------+------------+----------------------+------------------+
| bar  |      1    |     0      |  3                   | 2012-05-12 9:42  |
| bar  |      0    |     1      |  2                   | 2012-05-11 15:42 |
| bar  |      1    |     0      |  3                   | 2012-05-10 13:44 |
+------+-----------+------------+----------------------+------------------+

例如Item='foo'

+------+-----------+------------+----------------------+------------------+
| Item | Stock Up  | Stock Down | Running Stock Total  | Transaction Time |
+------+-----------+------------+----------------------+------------------+
| foo  |      1    |     0      |  4                   | 2012-05-12 11:07 |
| foo  |      2    |     0      |  3                   | 2012-05-11 10:02 |
+------+-----------+------------+----------------------+------------------+

就像......

SELECT 
  Item, {xyz} as 'Stock Up', {abc} as 'Stock Down',  `Running Stock Total`, `Transaction Time`
FROM
  `StockTransactions`
WHERE
  `Item`='foo'
HAVING 
  ('Stock Up'>0 or 'Stock Down'>0)

可以这样做吗？

Answer 1

SELECT   `Item`,
         `Stock Up`,
         `Stock Down`,
         `Running Stock Total`,
         `Transaction Time`

FROM (
  SELECT   `Item`,
           GREATEST(`Running Stock Total` - @`last_total`, 0) AS `Stock Up`,
           GREATEST(@`last_total` - `Running Stock Total`, 0) AS `Stock Down`,
           `Running Stock Total`,
           `Transaction Time`,
           @`last_total` := `Running Stock Total`
  FROM     `StockTransactions` JOIN (SELECT @`last_total` := 0) AS lt
  WHERE    `Item` = 'bar'
  ORDER BY `Transaction Time` ASC
) AS t

ORDER BY `Transaction Time` DESC

在sqlfiddle上查看。如果您对结果按交易时间的升序和额外的last_total列进行排序感到满意，那么外部查询显然可以省略。

Answer 2

我的解决方案基于这样的假设：Transaction Time每Item都是唯一的。

我通过我创建的帮助器视图模拟row_number()分析函数：

CREATE VIEW running_stock AS
SELECT s.item,s.running_total,s.transaction_dt,
  (SELECT count(*) FROM stock WHERE item=s.item
      AND transaction_dt <= s.transaction_dt) AS row_number
  FROM stock s
 ORDER BY 1, 4;

在视图到位后，您可以使用以下查询获得所需的结果：

SELECT c.item AS "Item",
  greatest(c.running_total - p.running_total, 0) AS "Stock Up",
  greatest(p.running_total - c.running_total, 0) AS "Stock Down",
  c.running_total AS "Running Total",
  c.transaction_dt AS "Transaction Time"
FROM running_stock c
LEFT JOIN running_stock p ON c.item = p.item
      AND p.row_number + 1 = c.row_number
WHERE c.row_number > 1
ORDER BY 1, 5;

您可以在SQL Fiddle上播放此查询。

Answer 3

一种解决方案可能是：

制作光标以一次选择每一行
检查值是否更改，如果是，请将信息插入#temp表
从#temp表中选择所有数据

如果您可以按顺序识别所有行，则可以使用while循环代替游标。

Answer 4

我会尝试设置包含旧股票价格的变量。首先按项目排序，以便您可以自己处理每个库存的所有数据。

然后你可以这样说 int counter = 0; decimal startingPrice = 0; 十进制成本= 0;

        var list = new List<Decimal>();
        Decimal[] positivePercentagesToTest = new Decimal[] { 1.02m, 1.03m, 1.04m, 1.10m, 100 };
        Decimal[] negativePercentagesToTest = new Decimal[] { 0.99m, 0.985m, 0.98m, 0.95m, 0.9m };

        for (int i = 0; i <= positivePercentagesToTest.Count() -1 ;i++ )
        {
            foreach (var s in stocks)
            {
                //if(s.Ticker == "BAC")
                {
                    if (counter == 0)
                    {
                        startingPrice = s.Open;
                    }
                    counter++;

                    var openPrice = s.Open;

                    if (openPrice > (startingPrice * positivePercentagesToTest[i]) || openPrice < (startingPrice * negativePercentagesToTest[i]))
                    {
                        //sell
                        //same as percentage gain
                        var percentage = openPrice/startingPrice - 1;

                        list.Add(Math.Round(percentage, 2));
                        counter = 0;
                    }

                }

            }

            var amount = list.Sum();
            var profitToAdd = new Profits();
            profitToAdd.Amount = amount;

这是C＃代码。如果你需要在sql中，请告诉我。这只是我会使用的逻辑。

Answer 5

我不知道您的SQL风格，但在Oracle中有LAG()和LEAD()分析函数，允许您从结果集中的上一行或下一行访问列值。您可以使用LAG()查看先前和当前结果之间的差异，并确定是上升还是下降。你的SQL中有类似的东西吗？

用于显示“总计”列更改的SQL查询

5 个答案: