Pass value in a Variable - sql

Question

I want to pass the value of 1 of my columns in my SELECT statements in a Variable.
Here's my sample code:
DECLARE #TotalExpense DECIMAL(18,2)
SELECT a.[Posting Date] AS [Check Date],
a.[Document No_] AS [Check Number],
a.[Vendor No_],
(
SELECT SUM(CASE WHEN GLEntry.[VAT Amount] <> 0 THEN CAST(GLEntry.Amount AS DECIMAL(18,2)) ELSE 0 END) FROM [BLI$Detailed Vendor Ledg_ Entry] DtldVendLedger
LEFT JOIN [BLI$G_L Entry] GLEntry
ON GLEntry.[Document No_] = (SELECT VendLedger.[Document No_] FROM [BLI$Vendor Ledger Entry] VendLedger
WHERE VendLedger.[Entry No_] = DtldVendLedger.[Vendor Ledger Entry No_])
WHERE DtldVendLedger.[Entry Type] = 2 AND DtldVendLedger.[Initial Document Type] = 2 AND DtldVendLedger.[Document No_] = a.[Document No_]
AND GLEntry.[Source Code] = 'PURCHASES' AND GLEntry.[G_L Account No_] NOT IN ('2003','1402','1403','1401')
) AS [Vatable],
(
SELECT SUM(CASE WHEN GLEntry.[VAT Amount] <> 0 THEN CAST(GLEntry.Amount * 0.12 AS DECIMAL(18,2)) ELSE 0 END) FROM [BLI$Detailed Vendor Ledg_ Entry] DtldVendLedger
LEFT JOIN [BLI$G_L Entry] GLEntry
ON GLEntry.[Document No_] = (SELECT VendLedger.[Document No_] FROM [BLI$Vendor Ledger Entry] VendLedger
WHERE VendLedger.[Entry No_] = DtldVendLedger.[Vendor Ledger Entry No_])
WHERE DtldVendLedger.[Entry Type] = 2 AND DtldVendLedger.[Initial Document Type] = 2 AND DtldVendLedger.[Document No_] = a.[Document No_]
AND GLEntry.[Source Code] = 'PURCHASES' AND GLEntry.[G_L Account No_] NOT IN ('2003','1402','1403','1401')
) AS [Input Tax],
(
SELECT SUM(CASE WHEN GLEntry.[VAT Amount] = 0 THEN CAST(GLEntry.Amount AS DECIMAL(18,2)) ELSE 0 END) FROM [BLI$Detailed Vendor Ledg_ Entry] DtldVendLedger
LEFT JOIN [BLI$G_L Entry] GLEntry
ON GLEntry.[Document No_] = (SELECT VendLedger.[Document No_] FROM [BLI$Vendor Ledger Entry] VendLedger
WHERE VendLedger.[Entry No_] = DtldVendLedger.[Vendor Ledger Entry No_])
WHERE DtldVendLedger.[Entry Type] = 2 AND DtldVendLedger.[Initial Document Type] = 2 AND DtldVendLedger.[Document No_] = a.[Document No_]
AND GLEntry.[Source Code] = 'PURCHASES' AND GLEntry.[G_L Account No_] NOT IN ('2003','1402','1403','1401')
) AS [Non-Vat]
I want to Sum the Vatable, Input Tax, and Nonvat then pass the value into a variable then that variable will be used in my SELECT statements.

Answer 1

I tried to rearrange your query a bit. In your query the part with the DtldVendLedger query inside the join condition should not be valid. If you got that to run I have no idea how.
Because of the way I think you're summing I don't think it matters whether you used outer joins or inner joins. The rows with null GLEntry count as zeroes anyway.
DECLARE #vatable DECIMAL(18, 2);
DECLARE #inputtax DECIMAL(18, 2);
DECLARE #nonvat DECIMAL(18, 2);
SELECT
#vatable = SUM(
CASE
WHEN GLEntry.[VAT Amount] <> 0
THEN CAST(GLEntry.Amount AS DECIMAL(18,2)) ELSE 0 END
),
#nonvat = SUM(
CASE
WHEN GLEntry.[VAT Amount] = 0
THEN CAST(GLEntry.Amount AS DECIMAL(18,2)) ELSE 0 END
)
FROM
A as a /* I'm assuming there was a FROM referencing a table "a" */
[BLI$Detailed Vendor Ledg_ Entry] DtldVendLedger
INNER JOIN
ON DtldVendLedger.[Document No_] = a.[Document No_]
LEFT OUTER JOIN [BLI$Vendor Ledger Entry] VendLedger
ON VendLedger.[Entry No_] = DtldVendLedger.[Vendor Ledger Entry No_]
LEFT OUTER JOIN [BLI$G_L Entry] GLEntry
ON GLEntry.[Document No_] = VendLedger.[Document No_]
WHERE
a.??? = ???
AND DtldVendLedger.[Entry Type] = 2
AND DtldVendLedger.[Initial Document Type] = 2
AND GLEntry.[Source Code] = 'PURCHASES'
AND GLEntry.[G_L Account No_] NOT IN ('2003','1402','1403','1401');
SET #inputtax = 0.12 * #vatable;