Question

我遇到了数据库的问题。

并尝试查询有多少交易有电影“Harry_Potter”？

所以我使用了SQL查询：

SELECT
COUNT(td.movie) AS number_of_occurrence,
td.transaction_number
FROM
TransactionDetails td,
MovieDetails md
WHERE
md.movie = Harry_Potter

但它要求Harry_Potter输入参数值为什么？相关的SQL语句是

CREATE TABLE TransactionDetails 
(
transaction_number INTEGER PRIMARY KEY,
movie VARCHAR(30) NOT NULL,
date_of_transaction DATE NOT NULL,
member_number INTEGER NOT NULL
)

CREATE TABLE MovieDetails
(
movie VARCHAR(30) PRIMARY KEY,
movie_type VARCHAR(3) NOT NULL,
movie_genre VARCHAR(10) NOT NULL
)

ALTER TABLE TransactionDetails
ADD CONSTRAINT member_number_fk FOREIGN KEY (member_number) REFERENCES    LimelightMemberDetails(member_number);

ALTER TABLE TransactionDetails
ADD CONSTRAINT transaction_number_drink_fk FOREIGN KEY (transaction_number) REFERENCES DrinkTransactionDetails(transaction_number);

ALTER TABLE TransactionDetails
ADD CONSTRAINT transaction_number_food_fk FOREIGN KEY (transaction_number) REFERENCES FoodTransactionDetails(transaction_number);

ALTER TABLE TransactionDetails
ADD CONSTRAINT movie_fk FOREIGN KEY (movie) REFERENCES MovieDetails (movie);

感谢您的帮助！如果我的数据库设计有任何问题，请告诉我！谢谢！

Answer 1

将查询更改为

SELECT 
COUNT(td.movie) AS number_of_occurrence, 
td.transaction_number 
FROM 
TransactionDetails td, 
MovieDetails md 
WHERE 
md.movie = "Harry_Potter"

看电影是一个字符串，你需要围绕你正在寻找的值的引号。

如果我没弄错，MS Access会“和SQL SERVER接受”

Answer 2

试试这个

md.movie = "Harry_Potter"

我猜，你只是错过了你要比较的字符串周围的引号。

Microsoft Access - 输入参数值为什么？

2 个答案: