TSQL Control Flow Logic - sql-server

Question

I am working on building a procedure that uses basic dynamic SQL. I want to use the result of the dynamic SQL (#query) in another part of said procedure. Below is a shorthand version of the code I am attempting to complete.
WITHOUT THE USE OF sp_executesql, how can I go about passing the result value of #query into the IF blocks?
DECLARE #table VARCHAR(MAX)
DECLARE #query VARCHAR(MAX)
DECLARE #map VARCHAR(MAX)
SET #table = 'SomeTable'
SET #query = '
;WITH Assignment AS
(
SELECT
''' + #table + ''' AS src
,Type
,RANK () OVER(ORDER BY COUNT(type) as rnk
FROM ' + #table + '
GROUP BY Type
)
SELECT Type
FROM Assignment
WHERE rnk = ''1'''
IF (#query = 'typeA')
BEGIN
/* preform an upsert dynamically */
END
IF (#query = 'typeB')
BEGIN
/* preform a delete dynamically */
END
IF (#query = 'typeC')
BEGIN
/* preform an alter dynamically */
END

Answer 1

Why are you testing #query right after it has been set with some SQL?
You could do it with a temp table:
Create Table #temp(type...)
SET #query = '
;WITH Assignment AS
(
SELECT
''' + #table + ''' AS src
,Type
,RANK () OVER(ORDER BY COUNT(type) as rnk
FROM ' + #table + '
GROUP BY Type
)
Insert Into #temp(type)
SELECT Type
FROM Assignment
WHERE rnk = ''1'''
You can also build your dynamic query in your if statement although I am not sure it would work in your case:
SET #q1 = '
;WITH Assignment AS
(
SELECT
''' + #table + ''' AS src
,Type
,RANK () OVER(ORDER BY COUNT(type) as rnk
FROM ' + #table + '
GROUP BY Type
)'
set #q2 = 'SELECT Type
FROM Assignment
WHERE rnk = ''1'''
Case When #type = 'A' then #query = #q1 + 'Insert into... ' + #q2
Case When #type = 'B' then #query = #q1 + 'Update... ' + #q2
Case When #type = 'B' then #query = #q1 + 'delete from where type in (' + #q2 + ')' end
If you change you mind, it is also easy with sp_executesql:
create table #temp(type int)
insert into #temp
exec sp_executesql #query
or if there are not thousands of rows:
declare #temp table(type int)
insert into #temp
exec sp_executesql #query
If there is only one row, still with sp_executesql and a parameter, this is the best option:
declare #type varchar(10)
SET #query = '
declare #type varchar(10)
;WITH Assignment AS
(
SELECT
''' + #table + ''' AS src
,Type
,RANK () OVER(ORDER BY COUNT(type) as rnk
FROM ' + #table + '
GROUP BY Type
)
SELECT #type = Type
FROM Assignment
WHERE rnk = ''1''';
exec sp_executesql #query, N'#type varchar(10)', #type = #type

Answer 2

This is one way to get data out of dynamic SQL
DECLARE #SQL VARCHAR(MAX)
--Dynamic SQL
SET #SQL = '
--Do anything you like in here as long as you select the results in the #Data Table format at the end
SELECT 132'
--How to get the result out of the dynamic SQL (into a table)
DECLARE #Data TABLE (Value INT)
INSERT INTO #Data(Value)
EXEC(#SQL)
--Get the result out of the table into a local (if you need to)
DECLARE #MyValue INT
SELECT #MyValue = Value FROM #Data
--Do what you like with the value now we are back in normal SQL
PRINT #MyValue