如何避免对mysql查询的子查询

Question

有4张桌子

team
---------------
id | teamname |
1  | lal      |
2  | sobuj    |

member
-----------------------
id | membername| team |
1  | sagor     | 1    |
2  | sumon     | 1    |

dps
---------------------------------------------------
id | member| team | deposit | refund | ddate      |
1  | 1     | 1    | 100     | 12     | 2016-09-01 |
2  | 2     | 1    | 120     | 34     | 2016-09-01 |
3  | 1     | 1    | 130     | 22     | 2016-09-01 |
4  | 3     | 1    | 120     | 0      | 2016-09-01 |

mvs
----------------------------------------------------
id | member| team | mvs_total| refund | ddate      |
1  | 1     | 1    | 100      | 12     | 2016-09-01 |
2  | 2     | 1    | 120      | 34     | 2016-09-01 |
3  | 1     | 1    | 130      | 22     | 2016-09-01 |
4  | 3     | 1    | 120      | 0      | 2016-09-01 |

这是我的查询：

$result=mysql_query(select * from member where team='1');
$row=mysql_fetch_array($result);
do{
    $aresult=mysql_query(select sum(deposit)-sum(refund)as balance from dps where member='$row[id]');
    $arow=mysql_fetch_array($aresult);
    echo $arow[balance];

    $bresult=mysql_query(select sum(mvs_total)as mvs_balance from mvs where member='$row[id]' and date1<='2016-09-01');
    $brow=mysql_fetch_array($bresult);
    echo $brow[mvs_total];

} while($row=mysql_fetch_array($result));

如何避免子查询或如何节省时间建议请提前感谢。

Answer 1

我在您的表结构中注意到的第一件事是列重复。
例如。 dps 和 mcs 表中不需要 team 列，因为从 member 列 [连接到 member 表]你可以很容易的找到dps或者mvs在哪个队伍下。

对于您当前的问题，您可以使用以下查询。

    SELECT member.id, 
       member.membername, 
       Sum(dps.deposit) - Sum(dps.refund)       AS balance, 
       Sum(mvs.mvs_total)                       AS mvs_balance, 
       Sum(loan.deposit) - Sum(loan.withdraw)   AS balance, 
       Sum(loan.deposit2) - Sum(loan.withdraw2) AS balance2, 
       Sum(loan.total) - Sum(loan.lpay)         AS outsstanding 
FROM   member AS member 
       LEFT JOIN dps AS dps 
              ON dps.member = member.id 
       LEFT JOIN mvs AS mvs 
              ON mvs.member = member.id 
       LEFT JOIN loan AS loan 
              ON loan.member = member.id 
       WHERE  member.team = 1 
       AND mvs.ddate <= '2016-09-01' 
       -- AND loan.team = '10'  
       -- AND loan.cs = 'Core' 
GROUP  BY member.id