来自 Grails 的 INNER JOIN HQL 查询

Question

我正在尝试弄清楚如何使这段代码工作：

def searchString = unchecked.join(",");
        searchString = searchString.replace("\"", "'")
        println("searchString: " + searchString);

        def matches=Employee.executeQuery("select e.id from Employee as e INNER JOIN Education as ed ON e.id = ed.employee_id INNER JOIN education_type AS et ON et.id = ed.type_id WHERE et.name  in (" +searchString + ")");

这是传递给 executeQuery 的查询字符串

select e.id from Employee as e INNER JOIN Education as ed ON e.id = ed.employee_id INNER JOIN education_type AS et ON et.id = ed.type_id WHERE et.name  in ('AA','BS')

我可以在 SQL Server 中运行它并返回正确的结果，但是我的 grails 代码抱怨：

Stacktrace follows:
org.hibernate.hql.ast.QuerySyntaxException: unexpected token: ON near line 1, column 59 [select e.id from Employee as e INNER JOIN Education as ed ON e.id = ed.employee_id INNER JOIN education_type AS et ON et.id = ed.type_id WHERE et.name  in ('AA','BS')]

那么我做错了什么？执行查询的域对象是否错误？

Answer 1

考虑这样做：

def employee = Employee.withCriteria {
    education {
        educationType {
            in("name", ["AA", "BS"])
        }
    }
}

Answer 2

HQL 与标准 SQL 略有/足够不同。假设 Hibernate 知道这些对象之间的关系，您可以将查询简化为

List<String> typeNames = unchecked.collect { it.replace("\"", "") }
String query = """FROM Employee e
                  WHERE e.education.educationType.name IN (:typeNames)"""
List<Employee> = Employee.executeQuery(query, [typeNames: typeNames])

在查询中使用命名参数或位置参数以防止 sql 注入非常重要。此外，如果您真的只想要员工 ID 列表而不是实例，您可以将 SELECT e.id 放回那里。也没有理由包含引号，因为当绑定参数时，它们将为您正在使用的数据库使用正确的引号，因为上面的代码 sn-p 也删除了引号，但您可能会重新考虑甚至让它们成为放在首位。