WHERE上的GQL错误 [英] GQL error on WHERE

问题描述

select from comments.Comment 
where ownerType == 'looks.Look' 
AND ownerName == 'Yakuza' order by date

我得到异常:

Portion of expression could not be parsed: AND ownerName == 'Yakuza'

此查询很好用:

select from comments.Comment 
where ownerType == 'looks.Look' 
order by date

这也是:

select from comments.Comment 
where ownerName == 'Yakuza' order by date

完整代码:

PersistenceManager pm = PMF.get().getPersistenceManager();
String query = "... query goes here ...";
List<Comment> comments = null;
try {
    comments = (List<Comment>) pm.newQuery(query).execute();
}
...

推荐答案

将"AND"替换为&&"

Replace "AND" with "&&"

  PersistenceManager pm = PMF.get().getPersistenceManager();
  try {
    Query query = pm.newQuery("select from " + Song.class.getName()
        + " where mArtist== '" +artist+
        "' &&  mTitle=='"+title+
        "' &&  mAlbum=='"+album+"'" );
    List<Song> list = (List<Song>) query.execute();
  } catch (RuntimeException e) {
    System.out.println(e);
    throw e;
  } finally {
    pm.close();
  }

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