java.sq.SQLException：找不到列

Question

我收到以下錯誤：

HTTP Status 500 - Request processing failed; nested exception is
org.springframework.jdbc.BadSqlGrammarException: StatementCallback; bad SQL grammar 
[SELECT id, name FROM track WHERE category_id = 1 ORDER BY name]; nested exception is
java.sql.SQLException: Column 'category_id' not found.

但是當我將錯誤中列出的非常選擇的語句復制並粘貼到mysql shell中時，我得到了結果，這是預期的，因為表track列為category_id 。

這個錯誤可能是什么原因？

以下是track的表create語句：

CREATE TABLE track (
 id SERIAL
,name VARCHAR(50)
,category_id BIGINT UNSIGNED -- This references a serial (bigint unsigned)
,CONSTRAINT track_id_pk PRIMARY KEY (id)
,CONSTRAINT track_category_id_fk FOREIGN KEY
  (category_id) REFERENCES category (id)
);

以下是我的dao類中關於track表的一些行：

private static final class TrackMapper implements RowMapper<Track> {
    @Override
    public Track mapRow(ResultSet resultSet, int rowNum) throws SQLException {
        Track track = new Track();
        track.setId(resultSet.getInt("id"));
        track.setName(resultSet.getString("name"));
        track.setCategoryId(resultSet.getInt("category_id"));
        return track;
    }
}
public List<Track> getTracks(int categoryId) {
    String sql = "SELECT id, name FROM track WHERE category_id = " + categoryId + " ORDER BY name";
    return jdbcTemplate.query(sql, new TrackMapper());
}

Answer 1

檢查您的SQL語句 - 您需要在列列表中包含category_id ：

String sql = "SELECT id, name, category_id FROM track WHERE category_id = " + categoryId + " ORDER BY name";

它失敗了，因為你試圖從ResultSet提取category_id並且它不在那里。