添加重复和MySQL连接

我有一个连接多个表的查询，我在

总和中提取了一些重复的值

我试过用一些

SELECT 
    po.vendor AS 'Factory', 
    po.doc AS 'PO#', 
    po.date AS 'Date Ordered', 
    po.due_by AS 'Est. Receive Date',
    po.status AS 'PO Status', 
    po.amount AS 'PO Total Amount', 
    ROUND(SUM(IF(b.status = 'Paid In Full', b.amount, '')),2) 'Amount Paid To PO',
    ROUND(SUM(IF(b.status != 'Paid In Full',b.amount, '')),2) 'Amount Billed But Not Payed',
    SUM(IFNULL(so.amount, 0)) as 'SO Amount Cont. Cust.',
    so.doc,
    SUM(IFNULL(d.amount, 0)) as 'Deposits on SO',
    SUM(IFNULL(i.amount, 0)) as 'Amount Invoiced Cont. Cust.',
    SUM(IFNULL(i.amount_remain, 0)) as 'Amount Remaining from Customer'

FROM po 

    LEFT JOIN 
        (SELECT bill.doc, bill.amount, bill.po_fk, bill.status FROM bill GROUP BY bill.doc) b
        ON concat('Purchase Order #', po.doc) = b.po_fk


    LEFT JOIN 
        (SELECT so.doc, so.amount FROM so GROUP BY so.doc) so 
        ON concat('Sales Order #', so.doc) = po.so_fk

    LEFT JOIN  
        (SELECT deposit.doc, deposit.amount, deposit.status, deposit.so_fk FROM deposit GROUP BY deposit.doc) d
        ON concat('Sales Order #', so.doc) = d.so_fk

    LEFT JOIN 
        (SELECT invoice.doc, invoice.amount, invoice.so_fk, invoice.amount_remain FROM invoice GROUP BY invoice.doc) i
        ON concat('Sales Order #', so.doc) = i.so_fk

    GROUP BY po.doc;

下面是一些结果

+---------------------------+-----------------+-------------------+-----------------------+---------+----------------+-----------------------------+--------------------------------+
| PO#                       | PO Total Amount | Amount Paid To PO | SO Amount Cont. Cust. | doc     | Deposits on SO | Amount Invoiced Cont. Cust. | Amount Remaining from Customer |
+---------------------------+-----------------+-------------------+-----------------------+---------+----------------+-----------------------------+--------------------------------+
| 12734-I,12736-I           |        53452.55 |              0.00 |              63931.16 | SO28292 |       34715.58 |                        0.00 |                           0.00 |
| 13303-I/13304-I           |        44080.29 |          88160.58 |             209554.44 | SO19842 |      118013.08 |                   112777.22 |                           0.00 |
| 160512JB-5                |         1095.00 |              0.00 |                  0.00 | NULL    |           0.00 |                        0.00 |                           0.00 |
| 160713JB-2                |          163.00 |            163.00 |                  0.00 | NULL    |           0.00 |                        0.00 |                           0.00 |
| 161103 MYA FLYOVER        |          937.52 |            870.05 |                349.87 | SO26797 |        1099.87 |                     1099.87 |                           0.00 |
| 161228-RG Assembly Blocks |          864.00 |            864.00 |                  0.00 | NULL    |           0.00 |                        0.00 |                           0.00 |
| 1852998                   |        39207.10 |          39207.10 |              51542.57 | SO19688 |           0.00 |                    51542.57 |                           0.00 |
| 1955463                   |        39327.21 |          39327.21 |              51664.96 | SO22327 |           0.00 |                    51664.96 |                           0.00 |
| 1957583                   |        35591.61 |          35591.61 |              47235.91 | SO22414 |           0.00 |                    47235.91 |                           0.00 |
| 1988860                   |        36373.72 |          34455.52 |              48356.20 | SO23363 |           0.00 |                    48356.20 |                           0.00 |
| 2068548                   |        36284.97 |          72569.94 |             192776.28 | SO25250 |           0.00 |                    96388.14 |                           0.00 |
| 2084384                   |        54111.82 |         108223.64 |             286526.04 | SO25651 |           0.00 |                   143263.02 |                           0.00 |
| 2084510                   |        54829.71 |         109659.42 |             289017.28 | SO25658 |           0.00 |                   144508.64 |                           0.00 |
| 2219389                   |        39066.53 |              0.00 |              51693.99 | SO29601 |           0.00 |                        0.00 |                           0.00 |
| 2219407                   |           34.70 |              0.00 |                  0.00 | NULL    |           0.00 |                        0.00 |                           0.00 |

然后只是为了验证它是否在添加值duplicate times。您可以看到SO25658上的第13行显示了
总和（IFNULL（so.amount，0））为“so amount Cont.Cust.”，
值为
289017.28

mysql> select * from so where doc= 'SO25658';
+--------+---------+--------+---------+----------+
| id     | doc     | status | date    | amount   |
+--------+---------+--------+---------+----------+
| 230632 | SO25658 | Billed | 10/7/16 | 72254.32 |
+--------+---------+--------+---------+----------+
1 row in set (0.00 sec)

总而言之，我如何确保使用多个
连接从查询中删除重复值

谢谢
 在子查询中求和，然后再按联接的值联接分组。太好了，谢谢@xQbert