Two or more results of one CASE statement in SQL - sql

Question

Is it possible to SELECT value of two or more columns with one shot of CASE statement? I mean instead of:
select
ColumnA = case when CheckColumn='condition' then 'result1' end
,ColumnB = case when CheckColumn='condition' then 'result2' end
Something like:
select case when CheckColumn='condition' then ColumnA='result1', ColumnB='result2' end
UPDATE
Just the same as we can do with the UPDATE statement:
update CTE
set ColumnA='result1', ColumnB='result2'
where CheckColumn='condition'

Answer 1

It is not possible with CASE expression.
For every column you need new CASE

Answer 2

It is not possible, but you could use a table value constructor as a work around to this, to store each value for columna and columnb against your check column:
SELECT t.CheckColumn,
v.ColumnA,
v.ColumnB
FROM dbo.YourTable AS t
LEFT JOIN
(VALUES
('Condition1', 'Result1', 'Result2'),
('Condition2', 'Result3', 'Result4'),
('Condition3', 'Result5', 'Result6')
) AS v (CheckColumn, ColumnA, ColumnB)
ON v.CheckColumn = t.CheckColumn;
If you have more complex conditions, then you can still apply this logic, but just use a pseudo-result for the join:
SELECT t.CheckColumn,
v.ColumnA,
v.ColumnB
FROM dbo.YourTable AS t
LEFT JOIN
(VALUES
(1, 'Result1', 'Result2'),
(2, 'Result3', 'Result4'),
(3, 'Result5', 'Result6')
) AS v (ConditionID, ColumnA, ColumnB)
ON v.ConditionID = CASE WHEN <some long expression> THEN 1
WHEN <some other long expression> THEN 2
ELSE 3
END;

Answer 3

The equivalent select to the update is:
select 'result1', 'result2'
. . .
where CheckColumn = 'condition';
Your select is different because it produces NULL values. There is an arcane way you can essentially do this with outer apply:
select t2.*
from . . . outer apply
(select t.*
from (select 'result1' as col1, 'result2' as col2) t
where CheckColumn = 'condition'
) t2;
This will return NULL values when there is no match. And, you can have as many columns as you would like.

Answer 4

What I understood from your question is that you want to update multiple columns if certain condition is true.
For such situation you have to use MERGE statements.
Example of using MERGE is as given on msdn here.
Code example:
-- MERGE statement for update.
USE [Database Name];
GO
MERGE Inventory ity
USING Order ord
ON ity.ProductID = ord.ProductID
WHEN MATCHED THEN
UPDATE
SET ity.Quantity = ity.Quantity - ord.Quantity;
More MERGE statement example here.

Answer 5

You could solve this maybe with a CTE or a CROSS APPLY, somehting like
DECLARE #tbl2 TABLE(inx INT, val1 VARCHAR(10),val2 VARCHAR(10));
INSERT INTO #tbl2 VALUES(1,'value1a','value1b'),(2,'value2a','value2b'),(3,'value2a','value2b');
UPDATE yourTable SET col1=subTable.val1,col2=subTable.val2
FROM yourTable
CROSS APPLY(
SELECT val1,val2
FROM #tbl2
WHERE inx=1 --YourCondition
) AS subTable