所以我有一张表“dump”：

_____________________________________
| id_seller | client | price | flag  |
|====================================|
|     1     |   a    |  12   | True  |
|     1     |   a    |  10   | True  |
|     1     |   a    |  13←  | True  |
|     1     |   a    |  14   | False |
|     1     |   a    |  9←   | False |
|     1     |   a    |  11   | False |
|     2     |   a    |  15←  | True  |
|     2     |   a    |  13   | True  |
|     2     |   a    |  14   | True  |
|     2     |   a    |  21   | False |
|     2     |   a    |  23   | False |
|     1     |   a    |  20←  | False |
|     1     |   b    |  14   | True  |
            [...]

我正试图获得一些客户和卖家的最低和最高价格，具体取决于以下标志：

_________________________________________________________
| min_price_flag0 | max_price_flag1 | client | id_seller |
|========================================================|
|         9       |       13        |    a   |    1      |
|         20      |       15        |    a   |    2      |
|         42      |       21        |    b   |    1      |
|         84      |       10.5      |    b   |    2      |
etc..

目前我正在使用此请求，但我不确定它的性能是否良好，也不确定它是否与聚合表中的其他select相关联：

SELECT min_price_flag0,
       max_price_flag1,
       client,
       id_seller
  FROM (
           SELECT min(price) AS min_price_flag0,
                  client,
                  id_seller
             FROM dump_table
            WHERE id_seller IN (1,2,3) AND 
                  client IN ("a", "b", "c") AND 
                  flag = "False"
            GROUP BY client
       )
       AS min_price_flag0_select
       INNER JOIN
       (
           SELECT max(price) AS max_price_flag1,
                  client,
                  id_seller
             FROM dump_table
            WHERE id_seller IN (1,2,3) AND
                  client IN ("a", "b", "c") AND 
                  flag = "True"
            GROUP BY client
       )
       AS max_price_flag1_select ON min_price_flag0_select.id_seller = max_price_flag1_select.id_seller AND 
                                    min_price_flag0_select.client = max_price_flag1_select.client

我不太擅长sql，对数据库的访问也非常有限，所以我正在寻找更好的选择建议。