select a.Project_PK,
PC.b_cost AS Sum_of_Cost, PC.b_estimate_cost AS Sum_of_Estimated_Cost, PQ.c_qty AS Sum_of_Quantity, PQ.c_estimate_quantity AS Sum_of_Estimated_Quantity FROM Projects a LEFT JOIN ( select b.project_pk, sum(b.cost) as b_cost, sum(b.estimate_cost) as b_estimate_cost from cost b group by b.project_pk, ) ProjectCost PC ON PC. project_pk = a.project_pk LEFT JOIN ( select c.project_pk, sum(c.qty) as c_qty, sum(c.estimate_qty) as c_estimate_qty from Quantity c group by c.project_pk, ) ProjectQty PQ ON PQ.project_pk = a.project_pk From: firebird-support@yahoogroups.com [mailto:firebird-support@yahoogroups.com] Sent: 16 September 2014 08:45 PM To: firebird-support@yahoogroups.com Subject: [firebird-support] Re: SubQuery Help >Select > a.Project_PK >, SUM(b.cost) AS Sum_of_Cost >, SUM(b.estimate_cost) AS Sum_of_Estimated_Cost >, SUM(c.quantity) AS Sum_of_Quantity >, SUM(c.estimate_quantity) AS Sum_of_Estimated_Quantity >FROM Projects a >LEFT JOIN Cost b ON a.project_pk = b.project_pk >LEFT JOIN Quantity c ON a.project_pk = c.project_pk >GROUP BY a.Project_PK Unfortunately, this gives the wrong result if there are multiple costs or quantities for any project. Assume the following (all for the same project) COST 1 2 Quantity 1 2 3 The sums that ought to be given is 3 and 6, whereas I'm pretty certain the above statement would yield 9 and 12. Rather than this solution, you should either use one or two CTEs or a corrected version of the original solution. So either something like with SumCost(Project_PK, Sum_of_Cost, Sum_of_Estimated_Cost) as (select p.Project_PK, sum(c.cost), sum(c.estimate_cost) from Projects p join Costs c on p.project_pk=c.project_pk group by 1) select p.Project_PK, c.Sum_of_Cost, c.Sum_of_Estimated_Cost, SUM(q.quantity) AS Sum_of_Quantity, SUM(q.estimate_quantity) AS Sum_of_Estimated_Quantity from Projects p left join SumCost c on p.project_pk=c.project_pk left join Quantity q on p.project_pk=q.project_pk group by 1, 2, 3 or Select p.Project_PK, (select sum(c.cost) from Costs c where p.project_pk=c.project_pk) as Sum_of_Cost, (select sum(c.estimate_cost)from Costs c where p.project_pk=c.project_pk) as Sum_of_Estimated_Cost, (select sum(q.quantity) from Quanties q where p.project_pk=q.project_pk) as Sum_of_Quantity, (select sum(q.estimate_Quantity) from Quantity q where p.project_pk=q.project_pk) as Sum_of_Estimated_Quantity from Projects p Looking at the alternatives, I actually think the latter (i.e. the original and not the CTE), seems to be the simplest solution. HTH, Set [Non-text portions of this message have been removed]
