将字符串数据类型插入数据库的问题

Question

我有以下带有子查询的插入查询：

INSERT INTO Order (time_of_purchase, cust_id) 
VALUES (NOW(), (SELECT cust_id FROM Customer WHERE first_name = "John" AND last_name = "Doe")) RETURNING reference_number

当我执行查询时，postgres returns 错误："ERROR: column "John" 不存在。SQL 状态：42703。字符：110

可能是什么问题？

Answer 1

使用 Single Quotes 而不是 double quotes。 " 使编译器将其视为标识符。试试这个插入

INSERT INTO Order (time_of_purchase, cust_id) 
SELECT NOW(),cust_id FROM Customer WHERE first_name = 'John' AND last_name = 'Doe'