i have an entity Settings

@Entity()
class Settings {
  @PrimaryKey(autoGenerate: true)
  int? id;
  String key;
  String? value;

  Settings(this.id, this.key, this.value);
}

and DAO for Settings

@dao
abstract class SettingsDao {
  @Query('SELECT * FROM Settings')
  Future<List<Settings>> findAll();

@Query("SELECT * FROM Settings WHERE key = 'update_date_time'")
  Future<Settings?> findByKey();
}

after execution this code

 SettingsDao settingsDao=sl.get<SettingsDao>();
    Settings? updateDataTime =  await  settingsDao.findByKey();

and updateDataTime == null, but

final allSettings = await settingsDao.findAll();

allSettings contains all my Settings entity

why updateDataTime is null? in allSettings list I have my Settings(6) , one of which has update_date_time in key field

and if i add in my Dao another method, if I want to retrieve a List instead of one entity

@Query("SELECT * FROM Settings WHERE key = 'update_date_time'")
  Future<List<Settings>> findByKey2();   

I has this error:

E/flutter (23265): [ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: Bad state: Unsupported query "SELECT * FROM Settings WHERE key = 'update_date_time'" for List return type. It should be SELECT, since DELETE, UPDATE, INSERT returns int type. E/flutter (23265): #0 QueryAdapter.queryList (package:floor_common/src/adapter/query_adapter.dart:53:7) E/flutter (23265): #1 _$SettingsDao.findByKey2 (package:vr360newtablet/vr360_database.g.dart:892:26)

tried to receive data via streams: null there too