sql if value is null not equal does not work

Question

I have the below query, but the AND pd.FROMLOC <> 'DMS' does not work if the column has {null} is there a workaround?

SELECT pd.wavekey, pd.orderkey, o.externorderkey, pd.pickdetailkey, pd.status, pd.fromloc, pd.loc, pd.sku, pd.qty, pd.adddate, SUBSTR(o.c_zip,1,3), O.SUSR4, od.cartonbreak  
FROM sprtict.pickdetail pd  
Join sprtict.ORDERS O on O.ORDERKEY = PD.ORDERKEY  
Join sprtict.ORDERDETAIL OD on OD.ORDERKEY = O.ORDERKEY and od.ORDERLINENUMBER = pd.ORDERLINENUMBER  
WHERE(PD.adddate BETWEEN (TRUNC(SYSDATE-1) + 21/24) AND (TRUNC(SYSDATE) + 21/24))  
AND od.cartonbreak NOT IN ('FLOORPICK', 'LIFTPICK', 'STRINGERS')  
AND pd.FROMLOC <> 'DMS'  
AND pd.LOC <> 'DMS'  
AND O.SUSR4 = '3P01'  
AND pd.wavekey = '0001520762'  
AND o.externorderkey = 'SP000044662873'  

Answer 1

Fixed, and nvl(pd.fromloc, 'NullFROMLOC') <> 'DMS'

Answer 2

I nvl is an Oracle command. This is a MS SQL Server forum.

However, I suggest you read this:
https://www.red-gate.com/simple-talk/sql/t-sql-programming/how-to-get-nulls-horribly-wrong-in-sql-server/