php  MySQL  Subtracting from separate queries
696
The goal is to subtract query 1 from query 2 and display it in a table. I can handle the
while ($row = mysql_fetch_array($result)) {
portion of the request, but I can't get the following to work. It is meant to take this months sales from last months to see where they stand in comparison.
$result = mysql_query("SELECT (
Select
User,
SUM(COMPUTERS) as COMPUTERSTotal,
SUM(LAPTOPCOMPUTERS) as LAPTOPCOMPUTERSTotal,
SUM(PCCOMPUTERS) as PCCOMPUTERSTotal,
SUM(KEYBOARDSUnits) as KEYBOARDSTotal,
SUM(MOUSEUnits) as MOUSETotal,
SUM(PRINTERSUnits) as PRINTERSTotal,
SUM(MISCUnits) as MISCTotal,
SUM(PACKAGES) as PACKAGESTotal,
(round(SUM(LAPTOPCOMPUTERS) / SUM(COMPUTERS) * 100,2)) as LAPTOPPercentage,
(round(SUM(PACKAGES) / SUM(PCCOMPUTERS) * 100,2)) as PACKAGEPercentage,
SUM(KEYBOARDSUnits + MOUSEUnits + PRINTERSUnits + MISCUnits) as PERIPHERALTotal,
round(SUM(KEYBOARDSUnits + MOUSEUnits + PRINTERSUnits + MISCUnits) / SUM(COMPUTERS),2) as PERIPHERALPERSALE,
((SUM(KEYBOARDSUnits + MOUSEUnits + PRINTERSUnits + MISCUnits) / SUM(COMPUTERS) * (SUM(COMPUTERS) * 1)) * (round(SUM(LAPTOPCOMPUTERS) / SUM(COMPUTERS) * 100,2))) as Ratio
FROM my_db
WHERE YEAR(`Created`) = YEAR(CURRENT_DATE  INTERVAL 1 MONTH)
AND MONTH(`Created`) = MONTH(CURRENT_DATE  INTERVAL 1 MONTH)
)

(
Select
User,
SUM(COMPUTERS) as COMPUTERSTotal,
SUM(LAPTOPCOMPUTERS) as LAPTOPCOMPUTERSTotal,
SUM(PCCOMPUTERS) as PCCOMPUTERSTotal,
SUM(KEYBOARDSUnits) as KEYBOARDSTotal,
SUM(MOUSEUnits) as MOUSETotal,
SUM(PRINTERSUnits) as PRINTERSTotal,
SUM(MISCUnits) as MISCTotal,
SUM(PACKAGES) as PACKAGESTotal,
(round(SUM(LAPTOPCOMPUTERS) / SUM(COMPUTERS) * 100,2)) as LAPTOPPercentage,
(round(SUM(PACKAGES) / SUM(PCCOMPUTERS) * 100,2)) as PACKAGEPercentage,
SUM(KEYBOARDSUnits + MOUSEUnits + PRINTERSUnits + MISCUnits) as PERIPHERALTotal,
round(SUM(KEYBOARDSUnits + MOUSEUnits + PRINTERSUnits + MISCUnits) / SUM(COMPUTERS),2) as PERIPHERALPERSALE,
((SUM(KEYBOARDSUnits + MOUSEUnits + PRINTERSUnits + MISCUnits) / SUM(COMPUTERS) * (SUM(COMPUTERS) * 1)) * (round(SUM(LAPTOPCOMPUTERS) / SUM(COMPUTERS) * 100,2))) as Ratio
FROM my_db
WHERE `Created` >= CURDATE()  INTERVAL DAY(NOW())  1 DAY
)");
Thanks in advance!
Answer
Solution:
You can't use a row of data as a value in an expression. You can only use a subquery as a value if it returns a single element (1 row containing one column). For what you're doing, you need to join the subqueries and then subtract each column.
I think you're also missing
GROUP BY User
in your queries; it makes little sense to select that column if you're not calculating the totals by user.Answer
Solution:
First use alias for both the queries. Then run one query that subtracts those queries.
Answer
Solution:
You need to use individual select query for all data, now you have used only one select statement, you need to rewrite it like this 
SELECT( Select num1 FROM table1 )  ( Select num1 FROM table2
),( Select num2 FROM table1 )  ( Select num2 FROM table2
)