更改 table 以更改时间范围 [WHERE/ALTER]

Question

编辑：当前运行 SQuirreL SQL v.3.8.0.

我创建并保存了一个 table，它使用 WHERE 语句在特定时间范围内提取客户数据。我将如何更新时间范围？我尝试使用 ALTER TABLE 函数来更改 WHERE 语句，但收到一条错误消息。

原版table

SELECT Customer,
AVG(CAST(ItemPrice AS FLOAT)) AS item_price, 
COUNT(DISTINCT(ReceiptIDDesc)) AS number_of_orders, 
SUM(CAST(ItemPrice AS FLOAT)) AS total_spend
INTO Customer_data_A
FROM Tacos 
Where (CAST(PurchaseDate AS DateTime) >= '01/01/2017 12:00') AND (CAST(PurchaseDate AS DateTime) <= '12/01/2017 12:00')
GROUP BY Customer

改变语句

ALTER TABLE Customer_data_A ALTER COLUMN * WHERE (CAST(PurchaseDate AS DateTime) >= '01/01/2017 12:00') AND (CAST(PurchaseDate AS DateTime) <= '11/01/2017 12:00')

这给了我以下错误信息：

错误：“*”附近的语法不正确。

SQL状态：S0001

错误代码：102

Answer 1

在大多数 SQL 方言中，您使用的查询基本上是 "Perform this query and store the result into a new table"。新的 table 与用于为其获取数据的查询之间没有任何关系。

您可能真正想要使用的是视图（始终显示给定查询的当前数据 - 认为 "named query"）或物化视图（实际上将数据存储在 table 中，但用户可以从查询的新结果触发数据刷新。

Answer 2

听起来您想要截断现有数据并加载（插入）现有 table 结构？

ALTER TABLE + ALTER COLUMN 将更多地用于更改数据类型或添加约束（即将 INT 列更改为 NUMERIC，或添加外键引用）。

TRUNCATE TABLE Customer_data_A;

INSERT INTO Customer_data_A
(Customer, ItemPrice, Number_Of_Orders, Total_Spend)
SELECT Customer
      ,AVG(CAST(ItemPrice AS FLOAT)) AS item_price
      ,COUNT(DISTINCT(ReceiptIDDesc)) AS number_of_orders
      ,SUM(CAST(ItemPrice AS FLOAT)) AS total_spend
FROM Tacos 
WHERE (CAST(PurchaseDate AS DateTime) >= '01/01/2017 12:00') AND (CAST(PurchaseDate AS DateTime) <= '11/01/2017 12:00')
GROUP BY Customer;

更改 table 以更改时间范围 [WHERE/ALTER]

Altering a table to change time frame [WHERE/ALTER]

sql

alter-table