如何在遊戲框架中使用Group By？

Question

我想在遊戲框架中使用Group By。請問有人能告訴我如何使用Group By play框架？

Answer 1

使用GroupBy在Ebean中的一種方法是使用SqlQuery。

// Necessary imports.. 
import com.avaje.ebean.Ebean; 
import com.avaje.ebean.Query; 

// SQL query. 
String sql = "select max(salary) as maximum_salary, min(salary) as minimum_salary, department_id from employee_details where joining_date > :date group by department_id"; 

// Will get the list of Sql rows. 
List<SqlRow> sqlRows = Ebean.createSqlQuery(sql).setParameter("date", "1995-10-21").findList(); 

// Getting first row of the list 
SqlRow sql_row = sqlRows.get(0); 

// Getting values of respective columns by using their name 
int maximumSalary = sql_row.getInteger("maximum_salary"); 
int minimumSalary = sql_row.getInteger("minimum_salary"); 
int departmentID = sql_row.getInteger("department_id"); 

Answer 2

您可以運行前rawsql。

String sql 
    = " select order_id, o.status, c.id, c.name, sum(d.order_qty*d.unit_price) as totalAmount" 
    + " from o_order o" 
    + " join o_customer c on c.id = o.kcustomer_id " 
    + " join o_order_detail d on d.order_id = o.id " 
    + " group by order_id, o.status "; 

RawSql rawSql = 
    RawSqlBuilder 
     // let ebean parse the SQL so that it can 
     // add expressions to the WHERE and HAVING 
     // clauses 
     .parse(sql) 
     // map resultSet columns to bean properties 
     .columnMapping("order_id", "order.id") 
     .columnMapping("o.status", "order.status") 
     .columnMapping("c.id",  "order.customer.id") 
     .columnMapping("c.name", "order.customer.name") 
     .create(); 


Query<OrderAggregate> query = Ebean.find(OrderAggregate.class); 
    query.setRawSql(rawSql)   
    // add expressions to the WHERE and HAVING clauses 
    .where().gt("order.id", 0) 
    .having().gt("totalAmount", 20); 

List<OrderAggregate> list = query.findList(); 

注意：不要忘了進口com.avaje.ebean *;

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