NEWBIE needs help

I have listed my code below. All I want to do is show all records for YESTERDAY.

I know how to show todays date. But how can I automatically calculate yesterdays date?

This statement 'am.local_receiving_time < SYSDATE' is what I'm currently using and it's just not what I want.

Cheers


select
am.message_group,' ',
DECODE(am.severity, 0, 'Unchanged',
1, 'Unknown',
2, 'Normal',
4, 'Warning',
8, 'Critical',
16, 'Minor',
32, 'Major')
as severity,' ',
nn.node_name,
substr(TO_CHAR(am.local_receiving_time,'DD-MON-YYYY HH24:MI:SS'),1,30),' ',
mt.text_part
from
opc_act_messages am,
opc_message_groups mg,
opc_msg_text mt,
opc_node_groups ng,
opc_nodes_in_group ngig,
opc_node_names nn
where
am.message_group <> 'OpC'
and mg.name <> 'Misc'
and am.local_receiving_time < SYSDATE
and (am.severity = 1 or am.severity = 4 or am.severity = 8 or am.severity = 16 or am.severity = 32)
and am.message_number = mt.message_number
and am.node_id = ngig.node_id
and am.node_id = nn.node_id
and ngig.node_group_id = ng.node_group_id
and ng.node_group_name = 'hp_ux'
group by
am.message_group,am.severity,nn.node_name,am.local_receiving_time,mt.text_part
order by 1,2,3,4,5;

quit;

I found the solution. I put this statement in my where clause so that only records from YESTERDAY are displayed.

and substr(TO_CHAR(am.local_receiving_time,'DD-MON-YYYY'),1,30) = substr(TO_CHAR(SYSDATE-1,'DD-MON-YYYY'),1,30)