Need Help on SQL - sql

Question

I actually found something that I could work on regarding my problem "Need help with sql query". But I would appreciate it if I can get an answer to my specific question.
I have 2 tables one is TRANSACTIONS and one is EXPENSES.
TRANSACTION:
transaction_id
emp_id
sales_date
total_sales
And
EXPENSES:
expenses_id
emp_id
expense_date
expenses1
expenses2
total_expenses
I would like to sum all the TRANSACTION.transaction_amount AS sales_sum WHERE TRANSACTION.sales_date = #sales_date and TRANSACTION.emp_id = #emp_id ..... and then, subtract the EXPENSES.total_expenses as expenses_deducted_sales WHERE EXPENSES.emp_id = TRANSACTION.emp_id AND TRANSACTION.sales_date = EXPENSES.expense_date
PLEASE HELP.. Thank you
Ex
transaction_id emp_id sales_date total_sales
1 101 11/11/2012 300
2 101 11/11/2012 400
3 101 11/11/2012 300
expenses_id emp_id expenses_date expenses1 expenses2 total_expenses
1 101 11/11/2012 100 100 200
2 102 12/12/2012 50 50 100
3 103 10/12/2012 200 200 400
expenses_deducted_sales = (300 + 400 + 300) - 200
I've tried the code given by AHiggins and came up with these:
SELECT
CashTransactionsTbl.emp_id,
CashTransactionsTbl.trans_date,
CashTransactionsTbl.total_amt - ISNULL(ExpensesTbl.total_expenses,0) AS expenses_deducted_sales
FROM
(
SELECT
emp_id,
trans_date,
SUM(total_amt) AS sales_sum
FROM CashTransactionsTbl
GROUP BY emp_id, trans_date
) tr
LEFT JOIN
ExpensesTbl ON
tr.emp_id = ExpensesTbl.emp_id AND
tr.trans_date = ExpensesTbl.trans_date
WHERE
tr.trans_date = 2014-07-10
but no I have this error that says:
"Operand type clash: date is incompatible with int"
Please help!

Answer 1

You need two derived tables: One with the transaction sum per employee, one with the expenses sum per employee. Full outer join These to get all records.
select
coalesce(t.emp_id, e.emp_id) as emp_id,
coalesce(t.sum_sales, 0) as sum_sales,
coalesce(e.sum_expenses, 0) as sum_expenses,
coalesce(t.sum_sales, 0) - coalesce(e.sum_expenses, 0) as expenses_deducted_sales
from
(
select emp_id, sum(total_sales) as sum_sales
from transaction
group by emp_id
) t
full outer join
(
select emp_id, sum(total_expenses) as sum_expenses
from expense
group by emp_id
) e on e.emp_id = t.emp_id;

Answer 2

You need to get the aggregate data from Transactions before you match that with the data from Expenses, like so:
SELECT
tr.Emp_ID,
tr.Sales_Date,
tr.Sales_Sum - ISNULL(Expenses.Total_Expenses,0) AS Expenses_Deducted_Sales
FROM
(
SELECT
Emp_ID,
Sales_Date,
SUM(Total_Sales) Sales_Sum
FROM Transactions
) tr
LEFT JOIN
Expenses ON
tr.Emp_ID = Expenses.Emp_ID AND
tr.Sales_Date = Expenses.Expenses_Date
WHERE
tr.Sales_Date = #sales_date -- this could also go under the 'FROM Transactions' statement

Answer 3

This is pretty rough but something like this would work:
Select T_Sales.*,T_Sales.totalsales-totalexpesnses 'Expenses_deducted_sales'
from (
select t.emp_id,sales_date,SUM(totalsales) 'totalsales'
from #transaction t
group by t.emp_id,sales_date
) T_Sales
left join #expenses e
on T_Sales.emp_id = e.emp_id
and T_Sales.sales_date = e.expenses_date
where sales_date = #sales_date
ps. Apologies for spelling - quick work.