SQL - using SET with a variable table value - sql

Question

This is my code:
DECLARE #LoopCounter INT = 1,#max INT,#table nvarchar(100),#academic nvarchar(100)
SELECT #max = max(id)
FROM #tablelist
WHILE(#LoopCounter <= #max)
BEGIN
SET #table = (SELECT TABLE_NAME
FROM #tablelist WHERE id = #LoopCounter)
SET #academic = (SELECT F6
FROM #table WHERE F5 = Academic)
SET #LoopCounter = #LoopCounter + 1
END
where #tablelist is a list of all my tables in the database that are relevent.
The step:
SET #academic = (SELECT F6
FROM #table WHERE F5 = Academic)
does not work... I've tried with sp_execute but I get thrown back standard errors, at the moment the error is 'Must declare the standard variable '#table'. I have also tried an EXEC but it doesn't like that either.
What I want to do is define #academic to be a value from the #table The problem I'm having is the SET does not like being from #table.
Any help would be fab!

Answer 1

I think you want dynamic SQL:
DECLARE #LoopCounter INT = 1,
#max INT,#table nvarchar(100),
#academic nvarchar(100);
DECLARE #SQL NVARCHAR(MAX);;
SELECT #max = max(id)
FROM #tablelist;
WHILE(#LoopCounter <= #max)
BEGIN
SET #table = (SELECT TABLE_NAME FROM #tablelist WHERE id = #LoopCounter) ;
SET #SQL = '
SELECT #academic = F6
FROM [table]
WHERE f5 = 'Academic'
';
SET #SQL = REPLACE(#SQL, '[Table]', #table_name);
EXEC sp_executesql #SQL,
N'#academic NVARCHAR(100)',
#academic=#academic;
SET #LoopCounter = #LoopCounter + 1
END;
All that said, this is not an example of good coding (even ignoring the fact that I'm not escaping the table name).
You should not have multiple tables with the same columns, distinguished only by a variant of the name. Instead, you should have a single table with all the rows, and perhaps an additional column or two for identifying the columns.
Having to use dynamic SQL can illustrate a problem with the data model. And in this case, I think that it does.