android - 用于 INNER JOIN 的 sqliteDatabase.query()

Question

我想从 Android SQLite 数据库中执行如下查询:

select place.permit_name, local.local_distance
from tblLocal local
inner join tblPlaces place
on place._id = local._id
order by local.local_distance asc

我正在尝试使用 query()，而不是 rawQuery()。我不知道如何指定 INNER JOIN/ON。我该怎么做？

final String table = PlacesDataContract.PlacesDataEntry.TABLE_NAME;
final String[] columns =  { PlacesDataContract.PlacesDataEntry.COLUMN_NAME_PERMIT_NAME. , LocalDataContract.LocalDataEntry.COLUMN_NAME_LOCAL_DISTANCE};
final String orderBy = LocalDataContract.LocalDataEntry.COLUMN_NAME_LOCAL_DISTANCE + " ASC"; 

Cursor cursor = sqLiteDatabase.query(table, // table
        columns, // columns
        null, // selection
        null, // selectionArgs
        null, // groupBy
        null, // having
        orderBy, // orderBy
        null); // limit

Answer 1

您可以将联接放在 table 变量中。

String table = "tblLocal local " +
    "inner join tblPlaces place " +
    "on place._id = local._id";

有关示例，请参阅 Google 的 IOSched 应用程序。看看 provider包和 SelectionBuilder类。

SQLiteQueryBuilder 用于构建查询字符串，它所做的只是将表变量连接到查询的其余部分。参见 https://android.googlesource.com/platform/frameworks/base/+/refs/heads/master/core/java/android/database/sqlite/SQLiteQueryBuilder.java#201