RdbPredicates能否支持查询 count 功能？

// 配置谓词 
let predicates = new relationalStore.RdbPredicates("Book"); 
if(this.rdbStore){ 
  await this.rdbStore.query(predicates,(err, resultSet) => { 
    if (err) { 
      console.error(`Query failed, code is ${err.code},message is ${err.message}`); 
      return; 
    } 
    console.info(`rowCount: ${resultSet.rowCount},columnCount: ${resultSet.columnCount}`); 
  }) 
}