Postgresql 使用JDBC编写查询

我正在使用JDBC和PostgreSQL，我必须做以下工作：

/*
 * Return list of film titles whose length is equal to or greater
 * than the minimum length, and less than or equal to the maximum
 * length.
 */
public List<String> getFilmTitlesBasedOnLengthRange(Connection connection,
                int minLength, int maxLength) {
        List<String> result = new LinkedList<String>();

        return result;
}

dv_电影关系为：

CREATE TABLE dv_film (
    film_id      integer, 
    title        varchar(50), 
    description  text, 
    length       smallint, 
    rating       mpaa_rating
);

我试图解决这个问题的方法是：

public List<String> getFilmTitlesBasedOnLengthRange(Connection connection,
                        int minLength, int maxLength) {
                List<String> result = new LinkedList<String>();

                PreparedStatement st = conn.prepareStatement("SELECT title FROM dv_film A, dv_film B WHERE (? >= (COUNT(length) ASC LIMIT 1)) AND (? >= (COUNT(length) DESC LIMIT 1));");

                return result;
        }

公共列表GetFilmTitleBasedOnLengtrange（连接，
int最小长度，int最大长度）{
列表结果=新建LinkedList（）；
PreparedStatement st=conn.prepareStatement（“从DVU胶片A、DVU胶片B中选择标题，其中（？>=（计数（长度）ASC限制1））和（？>=（计数（长度）描述限制1））；”；
返回结果；
}

您的声明：

PreparedStatement st = conn.prepareStatement("SELECT title FROM dv_film A, dv_film B WHERE (? >= (COUNT(length) ASC LIMIT 1)) AND (? >= (COUNT(length) DESC LIMIT 1));");

这里您试图将列名传递给PreparedStatement，而您不能将列名设置为PreparedStatement值。您只能设置 列值作为PreparedStatement值

PreparedStatement st = conn.prepareStatement("SELECT title FROM dv_film A, dv_film B WHERE (? >= (COUNT(length) ASC LIMIT 1)) AND (? >= (COUNT(length) DESC LIMIT 1));");