MYSQL 按列分组

Question

我有以下 MYSQL 输出

Type        | Unit | Model       |Ownership         
-----------------------------------------
Drill       | BM70 | DD110       | owned
Drill       | BM81 | DD110       | owned
Light Plant | X652 | 20 KW Tower | owned
Light Plant | LT12 | 20 KW Tower | rental
Light Plant | LT13 | 20 KW Tower | rental
Light Plant | G242 | 20 KW Tower | rental

我试图显示的是类型、型号和所有权，除非我获得所有权，否则它们都可以正常工作。我需要分解拥有和租赁之间的所有权，因此查询后显示的输出应如下所示

   Type        | Model        |Ownership         
    ------------------------------------
    Drill       | DD110       | owned
    Light Plant | 20 KW Tower | owned
    Light Plant | 20 KW Tower | rental

在 SQL 语句中，我使用 GROUP BY 所有权给了我第一行和第三行，但不是第二行。这是我的确切查询，任何帮助将不胜感激:

               $order = 'equipment_model_name';

               $get_equipment = "SELECT * FROM
                    rbs_equipment_type t
                        INNER JOIN
                    rbs_equipment_model m
                        ON t.id = m.model_type_id
                        INNER JOIN
                    rbs_equipment_unit u
                        ON m.model_id = u.equipment_unit_model_id
                    GROUP BY u.ownership
                    ORDER BY $order";

Answer 1

只需在 group by 子句中添加类型即可。由于您没有提供列名称，我会猜测类似:

GROUP BY t.type, u.ownership