Question

根据客户在sales表中购买多辆车的时间，创建一个显示customer表，customerFirName和customerZip的查询时出现问题。以下是表格创作：

CREATE TABLE CUSTOMERS
(customerID     INT     PRIMARY KEY,
customerFirName     VARCHAR(20) NOT NULL,
customerLasName     VARCHAR(20) NOT NULL,
customerMiName      VARCHAR(1)  NOT NULL,
customerStreet      VARCHAR(40) NOT NULL,
customerState       VARCHAR(15) NOT NULL,
customerCity        VARCHAR(20) NOT NULL,
customerZip     VARCHAR(15) NOT NULL);

CREATE TABLE SALES
(saleID         INT     PRIMARY KEY,
grossSalePrice      DECIMAL(9,2),
vehicleStatus       VARCHAR(10) NOT NULL CHECK (lower(vehicleStatus) IN ('available', 'sold', 'pending')),
saleDate        DATE,
saleMileage     INT,
customerID      INT,
salespersonID       INT,
vehicleVIN      VARCHAR(25),
CONSTRAINT SALES_FK1 FOREIGN KEY (customerID) REFERENCES CUSTOMERS(customerID);

这是所需的输出：

customerID        customerFirName    customerZip    Number_of_Sales
1                 Bob                12345          2
2                 Jim                94949          3
3                 Tom                99330          4

以下是我尝试过的内容....我在创建单个SELECT语句时出现问题，该语句具有内部联接以组合CUSTOMERS.customerID字段上的SALES.customerID字段。我哪里错了？谢谢！

SELECT CUSTOMERS.customerFirName, CUSTOMERS.CustomerID, CUSTOMERS.customerZip, COUNT(SALES.customerID)
FROM CUSTOMERS
INNER JOIN SALES ON CUSTOMERS.customerID=SALES.customerID
GROUP BY SALES.customerID
HAVING COUNT(SALES.customerID) > 1;

和

SELECT COUNT (CUSTOMERS.customerID), customerFullName, customerZip
FROM CUSTOMERS
INNER JOIN SALES ON CUSTOMERS.customerID=SALES.customerID
GROUP BY SALES.customerID
HAVING COUNT(SALES.customerID) > 1;

Answer 1

我猜这个问题在group by字段上。

SELECT CUSTOMERS.customerFirName, CUSTOMERS.CustomerID, CUSTOMERS.customerZip, 
COUNT(SALES.customerID)
FROM CUSTOMERS
INNER JOIN SALES ON CUSTOMERS.customerID=SALES.customerID
GROUP BY CUSTOMERS.customerFirName, CUSTOMERS.CustomerID, CUSTOMERS.customerZip
HAVING COUNT(SALES.customerID) > 1;

Answer 2

也许只是在子选择中进行计数：

select * from
(SELECT CUSTOMERS.customerFirName, CUSTOMERS.CustomerID, CUSTOMERS.customerZip, COUNT(*) num_sales
FROM CUSTOMERS
INNER JOIN SALES ON CUSTOMERS.customerID=SALES.customerID
GROUP BY CUSTOMERS.customerFirName, CUSTOMERS.CustomerID, CUSTOMERS.customerZip)
where num_sales > 1;

SQL Oracle Select，Count和Inner Join

2 个答案: