be careful switching the database to single_user if sql server agent is running with sysadmin privileges it will get the only active connection available.

to switch off the containement database...

This is not what you need ?

select

coalesce(p.period_month,r.Fromdate) as period_month,r.warehouse_code,r.item_number,r.origin_warehouse_code,r.Fromdate

from

Routing_History r

left join Period p on p.period_month= r.Fromdate

Try to isolate the error. Run this code out of the stored procedure and debug it to see where is the problem.

Then this should do the trick :

I think what you want is to query all routing_history rows and show period_month column only if available. This is a left join :

select

p.period_month,r.warehouse_code,r.item_number,r.origin_warehouse_code,r.Fromdate

from

Routing_History r

left join Period p...

What is the datatype of LH.hazardCode column ?

fragment count 2000 means that index data is spread accross 2000 blocks of consecutive pages.

A Fragment is a collection of pages in sequence

For example you can have data spread across 6 pages, but these pages are located in different extents :

...