SQL - Subquery Error and Sum Error - mysql

Question

The SQL code I have is shown below. The issue I am having is with the subquery first of all.
The result displays the error:
SQL ERROR: Subquery returned more than 1 value. This is not permitted
when the subquery follows =, !=, <, <= , >, >= or when the subquery is
used as an expression
Need to show rows with date greater than (or equal to) the date where ESource = Detail - The rows need to be summed in some columns and a single value selected in others.
Code used:
select DISTINCT
A.Policy,
A.Fund,
(SUM(A.AddUnits)) AS SUM,
((C.TotalUnits - (SUM(A.AddUnits))) * A.Price) AS Value,
Inner JOIN TableC C
ON C.PolicyNumber = A.PolicyNumber
where A.PolicyNumber = '120' AND C.NumberOfUnits > 0 AND C.InvestmentFund = A.InvestmentFund
AND A.DateOfEntry < DATEADD(year, -1, GetDate())
AND A.DateOfEntry >= (Select DateOfEntry FROM TableA AS D where D.ESource = 'Detail')
AND A.UnitPrice = (Select UnitPrice FROM TableA AS E where E.ESource = 'Detail')
ORDER BY IH.DateOfEntry DESC
Tables are:
Table A:
Policy Fund Units Price ESource Date
120 BR 6 0.74 RE 2015
120 BR -100 0.72 Detail 2014
120 BR 6 0.71 RE 2013
TABLE C:
Policy Fund TotalUnits
120 BR 400
DESIRED RESULT:
Policy Fund Sum Price Value
120 BR [6+(-100)] = -94 0.72 [(400+(-94))*0.72] = 220.32
As well as the sub query issues - the command to get price = 0.72 [where ="Detail"] is stopping the sum of both rows occurring making Sum = -100 and not -94
Any help with the errors would be greatly appreciated

Answer 1

The problem is in your where clause:
where A.PolicyNumber = '120' AND
C.NumberOfUnits > 0 AND
C.InvestmentFund = A.InvestmentFund AND
A.DateOfEntry < DATEADD(year, -1, GetDate()) AND
A.DateOfEntry >= (Select DateOfEntry FROM TableA AS D where D.ESource = 'Detail') AND
A.UnitPrice = (Select UnitPrice FROM TableA AS E where E.ESource = 'Detail')
The last two clauses are the problem. One way to fix this is with the keywords ANY, SOME, or ALL:
where A.PolicyNumber = '120' AND
C.NumberOfUnits > 0 AND
C.InvestmentFund = A.InvestmentFund AND
A.DateOfEntry < DATEADD(year, -1, GetDate()) AND
A.DateOfEntry >= ALL (Select DateOfEntry FROM TableA AS D where D.ESource = 'Detail') AND
A.UnitPrice = ALL (Select UnitPrice FROM TableA AS E where E.ESource = 'Detail')
However, I prefer explicit aggregation:
where A.PolicyNumber = '120' AND
C.NumberOfUnits > 0 AND
C.InvestmentFund = A.InvestmentFund AND
A.DateOfEntry < DATEADD(year, -1, GetDate()) AND
A.DateOfEntry >= (Select MAX(DateOfEntry) FROM TableA AS D where D.ESource = 'Detail') AND
A.UnitPrice = (Select MAX(UnitPrice) FROM TableA AS E where E.ESource = 'Detail')
Note that the query in your question seems to be missing a from clause. And the condition C.InvestmentFund = A.InvestmentFun should be in an on clause not in the where clause.