CASE WHEN to assign a result set to a query - sql

Question

I've been trying to assign different resultsets to a query depending on an input
Depending on the company selected a set of filtered results should be displayed, here's my code.
DECLARE #COMPANY VARCHAR(10) = 'Company_name1'
SELECT
(CASE
WHEN #COMPANY = 'Company_name1'
THEN (SELECT INVENTLOCATIONID FROM INVENTDIM INV
WHERE (INV.DATAAREAID = #COMPANY)
AND (((INVENTLOCATIONID IS NOT NULL)
AND ((WMSLOCATIONID IS NOT NULL)
AND (WMSLOCATIONID <> '')))
AND (INV.INVENTLOCATIONID = 'x5'))
WHEN #COMPANY = 'Company_name2'
THEN (SELECT INVENTLOCATIONID FROM INVENTDIM INV
WHERE (INV.DATAAREAID = #COMPANY)
AND (((INVENTLOCATIONID IS NOT NULL)
AND ((WMSLOCATIONID IS NOT NULL)
AND (WMSLOCATIONID <> '')))
AND (INVENTLOCATIONID IN ('X0', 'X1', 'X2', 'X3', 'X5', 'X6', 'X8', 'P6', 'P8')))
ELSE (SELECT INVENTLOCATIONID FROM INVENTDIM INV
WHERE (DATAAREAID = #COMPANY)
AND ((INVENTLOCATIONID IS NOT NULL)
AND ((WMSLOCATIONID IS NOT NULL)
AND (WMSLOCATIONID <> '')))
END) AS WHAREWOUSE
FROM
INVENTDIM INV
ORDER BY
INV.INVENTLOCATIONID
Why am I not allowed to do this?

Answer 1

Here's one way you could do this using a CASE expression. Use a constant to reject entries where the company name matches the specific cases and the location is not in your list. If the company isn't one of the special cases, then accept it.
DECLARE #COMPANY VARCHAR(10) = 'Company_name1';
SELECT WHAREHOUSE = INVENTLOCATIONID
FROM dbo.INVENTDIM
WHERE DATAAREAID = #COMPANY
AND INVENTLOCATIONID IS NOT NULL
AND WMSLOCATIONID IS NOT NULL
AND WMSLOCATIONID <> ''
AND 1 =
(
CASE
WHEN DATAAREAID = 'Company_name1'
AND INVENTLOCATIONID <> 'x5'
THEN 0
WHEN DATAAREAID = 'Company_name2'
AND INVENTLOCATIONID NOT IN ('X0','X1','X2','X3','X5','X6','X8','P6','P8')
THEN 0
ELSE 1
END
)
ORDER BY INVENTLOCATIONID;
Potentially a disaster for query plan reuse, though, unless DATAAREAID is unique.
This is definitely a better approach:
Can you create a new cross reference table to allow the database to map company to the inventlocationid? – Zynon Putney II
So say you had a mapping table like:
CREATE TABLE dbo.LocationMap
(
DATAAREAID varchar(10),
INVENTLOCATIONID char(2),
PRIMARY KEY(DATAAREAID, INVENTLOCATIONID
);
INSERT dbo.LocationMap(DATAAREAID,INVENTLOCATIONID)
VALUES
('Company_Name1', 'x5'),
('Company_Name2', 'X0'), ('Company_Name2', 'X1') -- , ...
Then your query becomes:
DECLARE #COMPANY VARCHAR(10) = 'Company_name1';
SELECT WHAREHOUSE = INV.INVENTLOCATIONID
FROM dbo.INVENTDIM AS INV
LEFT OUTER JOIN dbo.LocationMap AS lm
ON INV.DATAAREAID = lm.DATAAREAID
WHERE INV.DATAAREAID = #COMPANY
AND INV.INVENTLOCATIONID IS NOT NULL
AND INV.WMSLOCATIONID IS NOT NULL
AND INV.WMSLOCATIONID <> ''
AND (lm.INVENTLOCATIONID = INV.INVENTLOCATIONID
OR lm.DATAAREAID IS NULL)
ORDER BY INV.INVENTLOCATIONID;

Answer 2

Written as a single query this is equivalent logic. Depending on the size of your data it's possible that the if..else branching would work better.
SELECT INVENTLOCATINID
FROM INVENTDIM INV
WHERE
INV.DATAAREAID = #COMPANY AND INVENTLOCATIONID IS NOT NULL WMSLOCATIONID <> '' AND
(
#COMPANY = 'Company name1' AND INV.INVENTLOCATIONID = 'x5' OR
#COMPANY = 'Company_name2' AND INVENTLOCATIONID IN
('X0', 'X1','X2','X3','X5','X6','X8','P6','P8') OR
#COMPANY NOT IN ('Company name1', 'Company name2')
);

Answer 3

Try this below query to get desired output
DECLARE #COMPANY VARCHAR(10) = 'Company_name1'
declare #tblIL as table
(
INVENTLOCATIONID int
)
IF(#COMPANY = 'Company_name1')
BEGIN
insert into #tblIL(INVENTLOCATIONID) values ('x5')
END
ELSE IF(#COMPANY = 'Company_name2')
BEGIN
insert into #tblIL(INVENTLOCATIONID) values ('X0', 'X1','X2','X3','X5','X6','X8','P6','P8')
END
ELSE
BEGIN
insert into #tblIL(INVENTLOCATIONID) values SELECT DISTINCT INVENTLOCATIONID FROM INVENTDIM
END
SELECT INVENTLOCATIONID FROM INVENTDIM INV
WHERE INV.DATAAREAID = #COMPANY AND INVENTLOCATIONID IS NOT NULL AND WMSLOCATIONID IS NOT NULL AND WMSLOCATIONID <> ''
AND INV.INVENTLOCATIONID in (select INVENTLOCATIONID from #tblIL)