Try this code

declare @chargeCust varchar(50)

set @chargeCust = 'test001'

select top 5

dj.job_no

, dj.cust_cd

, dj.job_date_time

, dj.dlv_reqd_datetime_last

from daily_job dj

where

dj.job_date_time >getdate-7 and

((len(@chargeCust) > 0 and dj.cust_cd in (@chargeCust)) or (len(@chargeCust) = 0...