Hibernate、PostgreSQL 9 的 JPA NamedNativeQuery 语法错误答案

【问题标题】：JPA NamedNativeQuery syntax error with Hibernate, PostgreSQL 9Hibernate、PostgreSQL 9 的 JPA NamedNativeQuery 语法错误
【发布时间】：2015-09-01 13:23:16
【问题描述】：

我遇到了一个很奇怪的问题。我有在 sql server 上执行时完美运行的本机查询：

SELECT  date_time, GREATEST(sum(count_up - count_down) OVER (PARTITION BY date_trunc('day', result.date_time) ORDER BY date_time),0) AS cum_amt FROM   peoplecounting.result order  BY date_time;

但是，在 JPA 中将此查询用作本机查询会导致语法错误

@NamedNativeQueries({@NamedNativeQuery(
        name = "Result.getTotal",
        query = "SELECT  date_time, GREATEST(sum(count_up - count_down) OVER (PARTITION BY date_trunc('day', peoplecounting.result.date_time) ORDER BY date_time),0) AS cum_amt FROM   peoplecounting.result order  BY date_time;")})

public class Result implements Serializable {...

///

@Entity
@SqlResultSetMapping(name = "TotalResultMapping", entities = {@EntityResult(entityClass = TotalResult.class, fields = {@FieldResult(name = "total", column = "cum_amt"), @FieldResult(name = "date", column = "date_time")})})

public class TotalResult {

private static final long serialVersionUID = 1L;

public TotalResult() {
}


@Id Date date;

public Date getDate() {
    return date;
}

public void setDate(Date date) {
    this.date = date;
}

public Integer getTotal() {
    return total;
}

public void setTotal(Integer total) {
    this.total = total;
}

Integer total;

}

打电话时：em.createNativeQuery("Result.getTotal","TotalResultMapping").getResultList();

我明白了：

INFO  [stdout] (default task-44) Hibernate: Result.getTotal
WARN  [org.hibernate.engine.jdbc.spi.SqlExceptionHelper] (default task-44) SQL Error: 0, SQLState: 42601
ERROR [org.hibernate.engine.jdbc.spi.SqlExceptionHelper] (default task-44) Error: Syntax error at or near "Result"

【问题讨论】：

标签： java hibernate postgresql jpa

【解决方案1】：

所以问题是em.createNativeQuery(...) 不是正确调用NamedNativeQuery，为了做到这一点，我应该调用em.createNamedQuery(...)。但是，看到em.createNativeQuery(...) 不接受@SqlResultSetMapping，很难将结果映射到自定义类。

最终的解决方案是使用

 return em.createNativeQuery("SELECT  peoplecounting.result.date_time, GREATEST(sum(peoplecounting.result.count_up - peoplecounting.result.count_down) " +
            "OVER (PARTITION BY date_trunc('day', peoplecounting.result.date_time) " +
            "ORDER BY peoplecounting.result.date_time),0) AS cum_amt" +
            " FROM   peoplecounting.result" +
            " order  BY peoplecounting.result.date_time",
            "TotalResultMapping").getResultList();

这样我可以使用我的@SqlResultSetMapping，一切都很好。

【讨论】：

【解决方案2】：

SQLState 是 42601，这是语法错误，根据PosgreSQL's list of error codes。

尝试删除命名本机查询声明末尾的分号。尽管您在对数据库本身发出查询时使用了分号，但分号并不是查询本身的一部分。

因此，这可能有效（未经测试，但当您尝试向普通 JDBC 查询添加分号时，Oracle 遇到了类似的问题）：

@NamedNativeQueries({@NamedNativeQuery(
    name = "Result.getTotal",
    query = "SELECT  date_time, GREATEST(sum(count_up - count_down) OVER (PARTITION BY date_trunc('day', peoplecounting.result.date_time) ORDER BY date_time),0) AS cum_amt FROM   peoplecounting.result order  BY date_time")})

【讨论】：

删除分号并没有改变任何东西