-- example code for calculating working days
declare @StartDate date = '2000-01-01';
set DATEFIRST 1;
WITH
bh as
(
SELECT '2016-01-01' BankHoliday UNION ALL
SELECT '25-03-2016' BankHoliday UNION ALL
SELECT '28-03-2016' BankHoliday UNION ALL
SELECT...