How to replace the OR condition in the Oracle SQL query? - oracle

Question

I am using Oracle Database 12c Enterprise Edition Release 12.2.0.1.0 - 64bit Production
Can somebody please tell me how to rewrite the below cursor query so that
it does not use the "OR" clause in the where condition
for performance benefits.
Basically the OR condition should be removed appropriately in the query.
CURSOR c_picklist_dtl IS
SELECT DISTINCT pd.dc_code,
pd.storer,
pd.picklist_key,
pd.pickdetail_key,
pd.line_no,
pd.pick_type,
pd.case_id,
pd.order_type,
pd.sub_type,
pd.order_no,
pd.item,
pd.consignee,
pd.bin_code,
pd.lot,
pd.pallet_id,
pd.packkey,
pd.to_pick_qty,
am.bin_code dispatch_bin_code,
ph.wave_id,
ph.po_no,
pd.pick_area_type,
pd.assignment_id,
pd.pick_method,
pd.pack_method,
pd.ord_priority,
pd.pick_seq_no
FROM table1 ph,
table2 pd,
table3 ot,
table4 am
WHERE pd.dc_code = ph.dc_code
AND pd.storer = ph.storer
AND pd.picklist_key = ph.picklist_key
AND ph.dc_code = p_dc_code
AND ph.storer = p_storer
AND ( ( ph.po_no = p_order_no
AND p_order_prefix = 'X'
AND pd.pick_method = 'P'
AND pd.status = 'E'
)
OR ( ph.wave_id = p_order_no
AND p_order_prefix = 'W'
AND pd.pick_method = 'P'
AND pd.status = 'E'
)
)
AND pd.item = p_item
AND pd.consignee = p_consignee
AND pd.dc_code = ot.dc_code
AND pd.order_type = ot.order_type
AND pd.sub_type = ot.sub_type
AND am.dc_code(+) = ot.dc_code
AND am.dc_area(+) = ot.dispatch_area
AND pd.to_pick_qty > 0
ORDER BY pd.dc_code,
pd.item,
pd.consignee,
pd.pick_seq_no,
pd.pickdetail_key,
pd.line_no;
Thanks

Answer 1

Your OR clause is pretty much the same apart from one literal comparison and different matching column for one of the input parameters, which pretty much means you can replace:
AND ( ( ph.po_no = p_order_no
AND p_order_prefix = 'X'
AND pd.pick_method = 'P'
AND pd.status = 'E'
)
OR ( ph.wave_id = p_order_no
AND p_order_prefix = 'W'
AND pd.pick_method = 'P'
AND pd.status = 'E'
)
)
with just something like:
AND p_order_no = CASE WHEN p_order_prefix = 'X' THEN ph.po_no
WHEN p_order_prefix = 'W' THEN ph.wave_id
ELSE NULL
END
AND pd.pick_method = 'P'
AND pd.status = 'E'

Answer 2

You can avoid repeating the 2 tests which are the same.
To go further you need to know the application and understand the logic.
AND ( ( ph.po_no = p_order_no
AND p_order_prefix = 'X'
OR )
( ph.wave_id = p_order_no
AND p_order_prefix = 'W') )
AND pd.pick_method = 'P'
AND pd.status = 'E'
can replace
AND ( ( ph.po_no = p_order_no
AND p_order_prefix = 'X'
AND pd.pick_method = 'P'
AND pd.status = 'E'
)
OR ( ph.wave_id = p_order_no
AND p_order_prefix = 'W'
AND pd.pick_method = 'P'
AND pd.status = 'E'
)
)