显示不同的记录sqlite android

Question

我的光标返回记录两次,即使我将distinct设置为true:

返回myDataBase.query(true,DB_TABLE,new String [] {"rowid as _id",KEY_CONDITIONS},builder.toString(),symptoms,null,null,null,null);

仅供参考,

   public Cursor getData(String[] symptoms) {
    String where = KEY_SYMPTOMS + "= ?";
    String orStr = " OR "; 

    StringBuilder builder = new StringBuilder(where);
    for(int i = 1; i < symptoms.length; i++)
        builder.append(orStr).append(where);

    return myDataBase.query(true, DB_TABLE, new String[] 
            {"rowid as _id", KEY_CONDITIONS}, builder.toString(), symptoms, null, null, null, null);

}

或者我尝试更改为rawQuery

    return myDataBase.rawQuery("SELECT DISTINCT " + KEY_CONDITIONS + " FROM " 
    + DB_TABLE + " " + builder.toString() + symptoms.toString(), null);

我的LogCat说:

  03-02 22:57:02.634: E/AndroidRuntime(333): FATAL EXCEPTION: main
  03-02 22:57:02.634: E/AndroidRuntime(333): android.database.sqlite.SQLiteException: near "=": syntax error: , while compiling: SELECT DISTINCT conditions FROM tblSymptoms symptoms= ? OR symptoms= ?[Ljava.lang.String;@405550f8

请帮我确定一下这里似乎缺少什么.真的很感激任何帮助.

Answer 1

解决方案
您需要DISTINCT条件,但Android需要_id列是一个问题,因为您不能混合和匹配:SELECT _id, DISTINCT condition....但是,您可以使用该GROUP BY子句:

return myDataBase.query(DB_TABLE, new String[] {"rowid as _id", KEY_CONDITIONS}, 
        builder.toString(), symptoms, KEY_CONDITIONS, null, null);

说明
此查询:

return myDataBase.rawQuery("SELECT DISTINCT " + KEY_CONDITIONS + " FROM " 
    + DB_TABLE + " " + builder.toString() + symptoms.toString(), null);

因为传入String[] symptoms错误的参数而失败,请尝试:

return myDataBase.rawQuery("SELECT DISTINCT " + KEY_CONDITIONS + " FROM " 
    + DB_TABLE + " " + builder.toString(), symptoms);

这个查询:

return myDataBase.query(true, DB_TABLE, new String[] {"rowid as _id", KEY_CONDITIONS}, builder.toString(), symptoms, null, null, null, null);

失败,因为DISTINCT在看这两个 ID和状态栏.它相当于:SELECT DISTINCT(_id, conditions) ...你显然只想要不同的条件......