Question

如果在同一天，7天或14天的间隔内以相同/不同供应商的不同价格采购材料，如何使用SQL代码提取数据？我累了但不能为此做代码。我是SQL新手。

数据表 - 项目日期供应商物料数量NetPrice

Answer 1

MariaDB [sandbox]> DROP TABLE IF EXISTS T;
Query OK, 0 rows affected (0.11 sec)

MariaDB [sandbox]> CREATE TABLE T( Item INT ,Dt DATE ,Vendor INT, PRICE INT);
Query OK, 0 rows affected (0.16 sec)

MariaDB [sandbox]>
MariaDB [sandbox]> INSERT INTO T VALUES
    -> (1,'2017-06-12',1,10),(1,'2017-06-25',1,20),
    -> (1,'2017-06-26',1,30),(1,'2017-06-26',1,40),
    -> (2,'2017-06-26',1,10),(2,'2017-06-26',1,40),
    -> (3,'2017-05-26',1,10),(3,'2017-05-26',1,40),
    -> (4,'2017-06-20',1,10),(4,'2017-06-20',1,40),
    -> (5,'2017-06-12',1,10),(5,'2017-06-12',1,40);
Query OK, 12 rows affected (0.07 sec)
Records: 12  Duplicates: 0  Warnings: 0

MariaDB [sandbox]>
MariaDB [sandbox]> select s.item,
    -> max(case when src = 1 then s.prices else 0 end) as PricesToday,
    -> max(case when src = 2 then s.prices else 0 end) as Prices7,
    -> max(case when src = 3 then s.prices else 0 end) as Prices14
    -> from
    -> (
    -> SELECT 1 as src,item,COUNT(DISTINCT PRICE) Prices
    -> FROM T
    -> where dt = date(now())
    -> GROUP BY ITEM HAVING COUNT(DISTINCT PRICE) > 1
    -> union
    -> SELECT 2,item,COUNT(DISTINCT PRICE) Prices
    -> FROM T
    -> where datediff(date(now()),dt) <= 7
    -> GROUP BY ITEM HAVING COUNT(DISTINCT PRICE) > 1
    -> union
    -> SELECT 3,item,COUNT(DISTINCT PRICE) Prices
    -> FROM T
    -> where datediff(date(now()),dt) <= 14
    -> GROUP BY ITEM HAVING COUNT(DISTINCT PRICE) > 1
    -> ) s
    -> group by s.item;
+------+-------------+---------+----------+
| item | PricesToday | Prices7 | Prices14 |
+------+-------------+---------+----------+
|    1 |           2 |       3 |        4 |
|    2 |           2 |       2 |        2 |
|    4 |           0 |       2 |        2 |
|    5 |           0 |       0 |        2 |
+------+-------------+---------+----------+

Answer 2

创建触发器
然后你想将输出保存到另一个表中，所以创建新表。
这样的事情。

DELIMITER $$ 在your_good_old_table更新后创建TRIGGER check_price         对于每一行         开始             如果NEW.price＆lt;＆gt; OLD.price那么
                INSERT INTO your_new_better_table（newprice）                 VALUES（NEW.newprice）;             万一;         结束;     $$
    DELIMITER;

注意：编辑可以格式化代码吗？我不能用ctrl + k

Answer 3

以下查询检索所有记录，对于具有其他价格的相同物料，在14天内存在另一记录。更改14到7或0或您要检查的任何其他值。

select *
from mytable
where exists
(
  select *
  from mytable other
  where other.material = mytable.material
  and other.netprice <> mytable.netprice
  and abs(datediff(other.date, mytable.date)) <= 14 -- or 7 or 0
)
order by material, date, netprice;

如果价格在同一天，7天和14天的间隔变化，如何选择数据？

3 个答案: