PHP Database Query - Group by month - sql

Question

An edit per the suggestions:
$sql=
"SELECT SysproCompanyJ.dbo.InvMovements.StockCode,
SysproCompanyJ.dbo.InvMaster.Description,
SysproCompanyJ.dbo.InvMovements.TrnYear,
SysproCompanyJ.dbo.InvMovements.Warehouse,
SysproCompanyJ.dbo.InvMovements.TrnMonth,
SysproCompanyJ.dbo.InvMovements.TrnQty,
SysproCompanyJ.dbo.InvMovements.TrnValue
FROM SysproCompanyJ.dbo.InvMovements,
SysproCompanyJ.dbo.InvMaster
WHERE SysproCompanyJ.dbo.InvMovements.StockCode = SysproCompanyJ.dbo.InvMaster.StockCode
AND SysproCompanyJ.dbo.InvMovements.Warehouse = 'S2'
GROUP BY SysproCompanyJ.dbo.InvMovements.TrnMonth";
The sample DB data would be:
Stockcode | Description | TrnYear | Warehouse | TrnMonth | TrnQty | TrnValue
PN1 | Part Number 1 | 2013 | S2 | 1 | 100 | 10.00
PN2 | Part Number 2 | 2013 | S2 | 1 | 200 | 125.00
PN3 | Part Number 3 | 2013 | S2 | 1 | 200 | 60.00
PN1 | Part Number 1 | 2013 | S2 | 2 | 300 | 560.00
PN4 | Part Number 4 | 2013 | S2 | 2 | 400 | 30.00
PN5 | Part Number 5 | 2013 | S2 | 2 | 100 | 230.00
I'm trying to break down the data into separate tables grouped by month and then having a variable to sum the total TrnValue by month.
The current query as is gives the following error
Warning: odbc_exec() [function.odbc-exec]: SQL error: [Microsoft][ODBC SQL Server Driver][SQL Server]Column 'SysproCompanyJ.dbo.InvMovements.StockCode' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause., SQL state 37000 in SQLExecDirect in C:\wamp\www\dacs\S2_2.php on line 69

Answer 1

You can't use columns in the select statement unless they inside an aggregate function (min,max,sum,count,...) or are included in the Group By.
Try something like this:
SELECT SysproCompanyJ.dbo.InvMovements.Warehouse,
SysproCompanyJ.dbo.InvMovements.TrnYear,
SysproCompanyJ.dbo.InvMovements.TrnMonth,
Sum(SysproCompanyJ.dbo.InvMovements.TrnQty) as sum_TrnQty,
Sum(SysproCompanyJ.dbo.InvMovements.TrnValue) as sum_TrnValue
FROM SysproCompanyJ.dbo.InvMovements,
SysproCompanyJ.dbo.InvMaster
WHERE SysproCompanyJ.dbo.InvMovements.StockCode = SysproCompanyJ.dbo.InvMaster.StockCode
AND SysproCompanyJ.dbo.InvMovements.Warehouse = 'S2'
GROUP BY SysproCompanyJ.dbo.InvMovements.Warehouse,
SysproCompanyJ.dbo.InvMovements.TrnYear,
SysproCompanyJ.dbo.InvMovements.TrnMonth
Usually doesn't make sense to include varchar columns (Stockcode, Description) in any type of aggregate, and since they are different values, you probably don't want them in the Group By either.

Answer 2

When using GROUP BY in a SQL query, all fields shown should either be 'grouped' by or a calculated (aggregate) value.
For example;
SELECT city, count(*), avg(price) FROM properties GROUP BY city;
Which will produce something like;
City   |  count  |   Avg
Paris  |  3      |   166.666
Will count the number of rows per city. City is part of the 'group by'. 'count(*)' and 'avg(price)' are calculated columns(aggregate).
If we would introduce another column to the query, 'city';
SELECT country, city, count(*), avg(price) FROM properties GROUP BY city;
The query would give an error, because country is neither 'grouped' or a calculated value. This error is quite logical; city-names are not unique worldwide (e.g. 'Paris' USA and 'Paris' in France), so grouping by city alone, the database can not show a unique country name.
To resolve this, either include 'country' in the group by, or make it a calculated field;
SELECT country, city, count(*), avg(price) FROM properties GROUP BY country, city;
Will return the results grouped by country, then by city
Country | City | count | Avg
USA | Paris | 1 | 100.000
France | Paris | 2 | 200.000
Using a calculated value for country;
SELECT min(country), city, count(*), avg(price) FROM properties GROUP BY country, city;
Would return the results grouped by city, and the 'first' country in the group:
min(Country)| City | count | Avg
France | Paris | 3 | 166.666
Which is probably not logical; the results show 'France', but it includes results from Paris, USA