Have you tried to use any joins using a charindex or patindex clause such as:

DELETE t1

FROM table1 t1

JOIN table2 t2

...

What about using Jeff Moden's Tally table to parse the comma-delimited @Stores parameter. Store the parsed values into a temp table to directly join to the dbo.Stores table.

DISCLAIMER: The sample...

You may have to clarify what you need, as I am not certain about your exepected end result. I assume you want the "RegNo", along with the four calculated columns....

One possible method is to create a simple scalar function to return the value.

I assume you mean to not hard code the column names for the dynamic method. If you did intend to hard-code columns, then you can manually fill in the @tableCols...