Two interpretations of what I believe you can mean:
Have columns with different data:
SELECT CASE WHEN @a = 1 THEN
'yes'
ELSE
'no'
END AS answer
INTO tempTable
Create a table with different queries:
IF @a = 1
SELECT 'yes' AS answer
INTO tempTable2
ELSE
SELECT 'no' AS answer, 'other field' as other
INTO tempTable2