Dynamic SQL for CASE Statements to remove hardcode - sql

Question

I've a Dynamic SQL that is required to be optimized. I need to make CASE Expression Dynamic. I've a list of ATTRIBUTE_LIST & SCENARIO_LIST, that are provided below. I wrote a Function to get them Dynamically. How can I replace Three CASE Expression and make it Dynamic? I'm trying to avoid hard coding.
SET #ATTRIBUTE_LIST = 'symbol_type, currency, performing_status' -- INPUTS
SET #SCENARIO_LIST = 'historicalsimulation_1day_end_10dec2013, historicalsimulation_1day_end_11dec2013'
SELECT CASE
WHEN (GROUPING(Scenario_Name) = 1) THEN ''ALL''
WHEN (Scenario_Name = ''[BaseCase]'') THEN ''BaseCase''
ELSE ISNULL(Scenario_Name, '''')
END AS Scenario_Name,
CASE
WHEN (GROUPING(Symbol_Type) = 1) THEN ''ALL''
ELSE ISNULL(Symbol_Type, '''')
END AS Symbol_Type,
CASE
WHEN (GROUPING(Currency) = 1) THEN ''ALL''
ELSE ISNULL(Currency, '''')
END AS Currency,
CASE
WHEN (GROUPING(Performing_Status) = 1) THEN ''ALL''
ELSE ISNULL(Performing_Status, '''') \
END AS Performing_Status,
SUM(Value) AS ScenarioValue
FROM [20151005_171003_UserName_NT-22_Analysis_Tue] o
LEFT JOIN [20151005_171003_UserName_NT-22_Analysis_Tue_Position_Data] pld
ON o.Position_Unique_Identifier=pld.Position_Unique_Identifier
GROUP BY ' + #ATTRIBUTE_LIST + ' WITH CUBE) AS DATA
PIVOT ( Sum(scenariovalue)
FOR scenario_name IN (' + #SCENARIO_LIST + ')'

Answer 1

It appears you are using SQL Server. Here's a brute-force way of looping over your attributes and building a series of case expressions:
declare #cases nvarchar(max) = '';
declare #l varchar(max) = #ATTRIBUTE_LIST + ',';
declare #ofs int = 0;
declare #pos int = charindex(',', #l, #ofs + 1);
while #pos > 0
begin
if #cases <> '' set #cases = #cases + ',';
set #cases = #cases +
replace('
CASE WHEN (GROUPING(<COL>) = 1) THEN ''ALL''
ELSE ISNULL(<COL>, '''')
END AS <COL>',
'<COL>', substring(#l, #ofs + 1, #pos - #ofs - 1)
);
set #ofs = #pos;
set #pos = charindex(',', #l, #ofs + 1);
end
select #cases;