实体类关联

（1/4）inner join

    //inner join
    @Test
    public void innerJoinTest() {
        // 查询ID=1160799039167057920的城市的省份名称
        HqlHelper helper = HqlHelper.queryFrom(City.class);
        helper.join(HqlHelper.currTable, "province", "p")
              .fetchWithTable("p", "name", "provinceName")
              .eq("id", "1160799039167057920");
        Record tempRecord = helperService.getRecord(helper);
        System.err.println(tempRecord);
    }

结果：

    select
        province1_.name as col_0_0_ 
    from
        dodo_city city0_ 
    inner join
        dodo_province province1_ 
            on city0_.province_id=province1_.id 
    where
        city0_.id=? limit ?

Record [rawData={provinceName=福建}]

（2/4）left join

测试数据：admin表

测试数据：role表

    //left join
    @Test
    public void leftJoinTest() {
        // 角色左关联查询创建该角色的管理员，返回角色名称和管理员名称
        // 因为'超级角色'这个角色没有创建人，因为是left join ，所以返回的adminName=null
        HqlHelper helper = HqlHelper.queryFrom(Role.class);
        helper.fetchWithTable(HqlHelper.currTable, "name", "roleName")
              .leftJoin(HqlHelper.currTable, "admin", "a")
              .fetchWithTable("a", "name", "adminName");
        Records tempRecords = helperService.getRecords(helper, false);
        System.err.println(tempRecords);
    }

结果：

    select
        admin1_.name as col_0_0_,
        role0_.name as col_1_0_ 
    from
        dodo_role role0_ 
    left outer join
        dodo_admin admin1_ 
            on role0_.admin_id=admin1_.id

Records [rawData=[
    {adminName=超级管理员, roleName=总监}, 
    {adminName=码叔, roleName=经理}, 
    {adminName=null, roleName=超级角色}]]

（3/4）right join

测试数据：admin表

测试数据：role表

//right join
    @Test
    public void rightJoinTest() {
        // 角色右关联查询创建该角色的管理员，返回角色名称和管理员名称
        // 因为'报表管理员'这个管理员没有创建过角色，因为是right join ，所以返回的roleName=null
        HqlHelper helper = HqlHelper.queryFrom(Role.class);
        helper.fetchWithTable(HqlHelper.currTable, "name", "roleName")
              .rightJoin(HqlHelper.currTable, "admin", "a")
              .fetchWithTable("a", "name", "adminName");
        Records tempRecords = helperService.getRecords(helper, false);
        System.err.println(tempRecords);
    }

结果：

    select
        admin1_.name as col_0_0_,
        role0_.name as col_1_0_ 
    from
        dodo_role role0_ 
    right outer join
        dodo_admin admin1_ 
            on role0_.admin_id=admin1_.id

Records [rawData=[
    {adminName=超级管理员, roleName=总监}, 
    {adminName=码叔, roleName=经理}, 
    {adminName=报表管理员, roleName=null}]]

（4/4）full join

    //full join
    @Test
    public void fullJoinTest() {
        // 查询具有相同名称的省份和城市，取一条记录
        HqlHelper helper = HqlHelper.queryFrom(City.class);
        helper.join(Province.class, "p")
              .fetchWithTable("p", "name", "provinceName")
              .eqProperty(HqlHelper.currTable, "name", "p", "name");
        Record tempRecord = helperService.getRecord(helper);
        System.err.println(tempRecord);
    }

结果：

    select
        province1_.name as col_0_0_ 
    from
        dodo_city city0_ cross 
    join
        dodo_province province1_ 
    where
        city0_.name=province1_.name limit ?

Record [rawData={provinceName=香港}]