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# Total amounts from two different tables.

I have three tables as shown below.  Table A is a list of shipments.  Table B is a list of Charges for each shipment. Table C is a list of charges on each invoice.

Table A (ShipID is a auto increment)
ShipID  Recipient
1         Mary Boyd
2         Tom Delay
3         George Bush

Table B  (ChargeID is a auto increment, ShipID is a foreign key)
ChargeID   ShipID  ChargeType  ChargeAmount
1              1         BaseCharge    6.00
2              1         Fuel               6.00
3              2         BaseCharge    12.50
4              2         Fuel               3.00
5              3         CustomsFees  55.00

Table C (ChargeID is a foreign key)
ChargeID  Amount   Invoice#
1             6.00      55245
2              5.00       55245
3              9.00       55246
3              3.50       55247
4              3.00       55246
5             49.00      55248

There can be multiple records in Table C for each record in Table B and there can be multiple records in Table B for each in Table A.
I need a sql statement that can display the following information.

ShipID  TotalChargedAmount   TotalInvoiceAmount    Balance
1                12.00                          11.00                  1.00
2                15.50                          15.50                  0.00
3                55.00                          49.00                  6.00

I have one statement but it take a really long time to calculate.  I need a fast sql statement.  The following statement takes about 25 seconds.  I need a very quick statement (under 1 sec)  I have about 10000 records in each table.

select TableA.ShipID, sum(TotalBilledSQL.TotalBilled) AS `AmountPaid`,sum(TotalChargeSQL.TotalCharges) AS `OrigAmount`
,(sum(TotalChargeSQL.TotalCharges)- sum(TotalBilledSQL.TotalBilled)) AS `Balance` from ((TableA left join (SELECT TableB.ShipID, sum(TableB.ChargeAmount) AS TotalCharges FROM TableB GROUP BY TableB.ShipID) AS TotalChargeSQL on((TableA.ShipID = TotalChargeSQL.ShipID))) left join (SELECT TableB.ShipID, sum(TableC.Amount) as TotalBilled FROM TableC RIGHT JOIN TableB ON TableB.ChargeID = TableC.ChargeID GROUP BY TableB.shipid) as TotalBilledSQL  on((TableA.shipid = TotalBilledSQL.ShipID))) group by TableA.ShipID
0
dyzenment
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1 Solution

Commented:
What are your definitions for TotalChargedAmount, TotalInvoiceAmount, Balance?

If Total Charged is the sum of all charges, Total Invoice is the sum of all invoiced amounts - and Balance is the difference between the two

*********************************************
Select
Summary.ShipId,
Summary.TotalChargedAmount,
Summary.TotalBilledAmount,
(Summary.TotalChargedAmount -      Summary.TotalBilledAmount) Balance
From
(
Select
A.ShipId,
(Select sum(B.ChargeAmount) from Table_B B where B.ShipID = A.ShipID) TotalChargedAmount,
(Select sum(C.Amount) from Table_C C, Table_B B where C.Charge_ID = B.ChargeID and B.ShipID = A.ShipID) TotalBilledAmount
From
Table_A A
) Summary
*********************************************
0

Commented:
It may not just be the query - you might need to improve your indexes; configuration and may need to specifically reference the indexes in the query for optimum performance.
0

Commented:
I think it would make sense to add 'totalcharged', 'totalinvoiced', and 'balance' columns to table A.  If that's not possible, I would do it with a temporary table.  I have an irrational dislike for subselects.

What types are you using for your monetary values?  Decimal(12,2) or something similar, right?  If you use doubles you can have subtle problems with inequality and rounding.

CREATE TEMPORARY TABLE balances (shipID int primary key, totalcharged decimal(12,2) not null default 0, totalinvoiced decimal(12,2) not null default 0, balance decimal(12,2) not null default 0);

INSERT INTO balances (shipID) select shipID from A;
UPDATE balances, B SET totalcharged = totalcharged + ChargeAmount WHERE balances.shipID = B.shipID;
UPDATE balances, B, C SET totalinvoiced = totalinvoiced + C.Amount WHERE balances.shipID = B.shipID and B.invoiceID = C.invoiceID;
UNLOCK TABLES;

-- now all the information you need is in the balances temporary table
SELECT shipID, totalcharged, totalinvoiced, (totalcharged - totalinvoiced) AS balance FROM balances;
0

Commented:
I am inclined to disagree with Nova - depending on how often a table is referenced then I would not always make temporary tables.  I find that as they write to disk and need cleaning up - they can take quite some time and are unnecessary.

SubSelects are in the ANSI standard and MySql handles them well.  A sub select is where you do sub queries and then reference them in an outer query - the reason I wrote the above query the way I did is so you are only totaling each piece of data once - then working with the sub totals.

Another option that you could use to increase the speed is to create a view - that does what Nova's temporary table does - which is in effect a compiled query; this would run faster than a temporary table as it is already memory resident and would give you the same result.

0

Commented:
select x.shipid, x.chg_amt, y.inv_amt, (x.chg_amt - y.inv_amt) balance
from
(select shipid, sum(chargeamount) chg_amt
from tableb
group by shipid) x
,(select c.shipid shipid, sum(i.amount) inv_amt
from tableb b
,tablec c
where b.chargeid = c.chargeid
group by b.shipid) y
where x.shipid = y.shipid
;
0

Commented:
Sorry, I used different aliases in my test..

select x.shipid, x.chg_amt, y.inv_amt, (x.chg_amt - y.inv_amt) balance
from
(select shipid, sum(chargeamount) chg_amt
from tableb
group by shipid) x
,(select b.shipid shipid, sum(c.amount) inv_amt
from tableb b
,tablec c
where b.chargeid = c.chargeid
group by b.shipid) y
where x.shipid = y.shipid
;
0

Commented:
Didn't see any reason to join tablea since it didn't appear you were trying to get the recipient name.
0
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