How to get sp_executesql result into a variable?

Question

I have a piece of dynamic SQL I need to execute, I then need to store the result into a variable.

I know I can use sp_executesql but can't find clear examples around about how to do this.

Answer 1

DECLARE @vi INT
DECLARE @vQuery VARCHAR(1000)

SET @vQuery = 'SELECT @vi= COUNT(*) FROM <TableName>'

EXEC SP_EXECUTESQL 
        @Query  = @vQuery
      , @Params = N'@vi INT OUTPUT'
      , @vi = @vi OUTPUT

SELECT @vi

Answer 2

If you have OUTPUT parameters you can do

DECLARE @retval int   
DECLARE @sSQL nvarchar(500);
DECLARE @ParmDefinition nvarchar(500);

DECLARE @tablename nvarchar(50)  
SELECT @tablename = N'products'  

SELECT @sSQL = N'SELECT @retvalOUT = MAX(ID) FROM ' + @tablename;  
SET @ParmDefinition = N'@retvalOUT int OUTPUT';

EXEC sp_executesql @sSQL, @ParmDefinition, @retvalOUT=@retval OUTPUT;

SELECT @retval;

But if you don't, and can not modify the SP:

-- Assuming that your SP return 1 value
create table #temptable (ID int null)
insert into #temptable exec mysp 'Value1', 'Value2'
select * from #temptable

Not pretty, but works.

Answer 3

This was a long time ago, so not sure if this is still needed, but you could use @@ROWCOUNT variable to see how many rows were affected with the previous sql statement.

This is helpful when for example you construct a dynamic Update statement and run it with exec. @@ROWCOUNT would show how many rows were updated.

Here is the definition