As the column names are not static, doing this dynamically is probably the only way you will get this to work.

The answer is 'almost certainly'.

Now, if you will take the...

I hate it when something fails, but only some of the time. Makes troubleshooting all the more challenging.

Can you see any sort of pattern between executions which succeed and those...

OK, then check the SSISDB 'All Executions' report (assuming the package is deployed to SSISDB). It should tell you which component the package fails on.

Is the error happening in SSDT? If so, you should be able to see from the Output window exactly which component is causing the error.

Is your Expression task empty? Maybe...

I suspect that the problem does not occur when the update is performed, instead, the column does not exist and therefore the error occurs at parse time, just before execution.

There...

In my opinion, this is something which you should definitely fix.

But if you use

SELECT DISTINCT cols

rather than

SELECT cols

any duplicate rows will be removed.

There is no need to use script tasks to set the value of variables - use Expression tasks for that.

If you want to set a variable to indicate a file's...

Please tell me you're not creating temp tables 1TB and larger.

@phil-parkin: do you mean use the "Foreach Loop Container"? Would I then have in the container Expression Tasks or a Script Task?

Yes, that's it.

Configure the 'Collection' node properties as follows:

...

My preferred way of handling such things is to use a FOREACH container. The contents of the (appropriately configured) FOREACH container will execute only if the specified file is found,...

Are you suggesting that if you could go back...

If I run this

SELECT CurrencyHashKey = CONVERT(CHAR(40), HASHBYTES('SHA1', LTRIM(RTRIM(COALESCE('USD', '')))), 2);

I get

57814CFBAE5C6D00F5CAB49E34B9AA2CE8269EB9

Without knowing more about dbo.[spAmount_V1], I can't do that.

Please post the 'signature' of that proc. That is, the following bit

CREATE PROCEDURE <procname> <parameters>

AS

In particular, you should have an OUTPUT parameter...

Stored procedures return results differently from functions. Here is an example proc and how to call it:

CREATE PROCEDURE dbo.DuffProc @RetValue VARCHAR(50) OUTPUT
AS
BEGIN
    SET @RetValue...