Join 3 tables, return records which no match found in table 1 as null

Question

Hi Gurus,
I really need your expert advice. I am stuck in below query.
I have joined 3 tables,
table 2 is an information reference (to get the process code and process name)
table 1 have and table 3 have daily data (which will have the process code and its values/qty)
all values return from table 1 and 3(rtrwip00 and prdyld01) should refer to code in table 1.
There can be a scenario where on a day, a process was stop, so it dont have values/qty in table 1/3,
The problem is my query will return only rows which have records in table 1/3.
While I want all the records in table 2 to be returned no matter have data or not in table 1/3, in case no data in table 1/3, return qty as '0'.
Please advice me..thanks in advance :)
Select lot.rw_oper,
lot.rw_area_grp,
lot.rw_oper_name,
proc_out.proc_out,
lot.rw_qty
from
( SELECT UNIQUE a.rw_oper,a.rw_area_grp,a.rw_oper_name,SUM(CASE WHEN a.rw_qty_unit = 'CM' THEN a.rw_qty*10 ELSE rw_qty END )as rw_qty
From rtrwip00 a, oprinf99 b
WHERE a.rw_facility='MIPOPRD'
AND b.oi_facility = a.rw_facility AND b.oi_oper = a.rw_oper
GROUP BY a.rw_area_grp,a.rw_oper,a.rw_oper_name
ORDER BY a.rw_oper,a.rw_area_grp) lot,
( SELECT py_oper, SUM(CASE WHEN py_out_unit1 = 'CM' THEN py_proc_out1*10 ELSE py_proc_out1 END) proc_out
FROM prdyld01
WHERE py_facility = 'MIPOPRD'
AND py_trs_time between TO_CHAR(SYSDATE-1,'YYYYMMDD')||'070000' AND TO_CHAR(SYSDATE,'YYYYMMDD')||'070000'
group by py_oper
)proc_out
where lot.rw_oper NOT IN ('2900','6700' ,'9100' ,'9920' ,'9921','9940','9941','9300','9500','6700','8910', 'REJT')
and lot.rw_oper = proc_out.py_oper
order by lot.rw_oper

Answer 1

CREATE TABLE PRDYLD01
PY_FACILITY VARCHAR2(12 BYTE) NOT NULL,
PY_TRS_TIME VARCHAR2(14 BYTE) NOT NULL,
PY_LOT VARCHAR2(11 BYTE) NOT NULL,
PY_OPER VARCHAR2(4 BYTE) NOT NULL,
PY_PO VARCHAR2(12 BYTE) NOT NULL,
PY_PROC_IN1 NUMBER(10,2) DEFAULT 0 NOT NULL,
PY_PROC_IN2 NUMBER(10,2) DEFAULT 0 NOT NULL,
PY_PROC_OUT1 NUMBER(10,2) DEFAULT 0 NOT NULL,
PY_PROC_OUT2 NUMBER(10,2) DEFAULT 0 NOT NULL,
sample data 1
PY_OPER     PROC_OUT
3000     481
3100     214
3200     642
3250     291
5250     519
5300     439
5350     476
CREATE TABLE RTRWIP00
RW_FACILITY VARCHAR2(12 BYTE) NOT NULL,
RW_LOT VARCHAR2(11 BYTE) NOT NULL,
RW_OPER VARCHAR2(4 BYTE) NOT NULL,
RW_OPER_NAME VARCHAR2(35 BYTE) NOT NULL,
RW_PO VARCHAR2(12 BYTE) NOT NULL,
RW_AREA_GRP VARCHAR2(12 BYTE) NOT NULL,
RW_QTY NUMBER(10,2) DEFAULT 0 NOT NULL,
RW_QTY_UNIT VARCHAR2(6 BYTE) NOT NULL,
sample data 2     
RW_OPER     RW_QTY
3000     1248
3100     324
3200     133
3250     357
4400     424
4500     821
4600     909
5050     689
5250     2472
5300     53
5350     166
CREATE TABLE OPRINF99
OI_FACILITY VARCHAR2(12 BYTE) NOT NULL,
OI_OPER VARCHAR2(4 BYTE) NOT NULL,
OI_OPER_SEQ NUMBER(5) NOT NULL,
OI_AREA_GRP VARCHAR2(12 BYTE),
OI_SHORT_DESC VARCHAR2(10 BYTE) NOT NULL,
OI_LONG_DESC VARCHAR2(35 BYTE),
sample data 3          
RW_OPER     RW_AREA_GRP     RW_OPER_NAME
3000     MOD     ROD MOUNT
3100     MOD     WIRE SAW
3200     MOD     AS-CUT CLEANER
3250     MOD     BEAM REMOVAL
4400     POL     ESE-II
4500     POL     EDGE OXIDE STRIP
4600     POL     LTO INSPECTION
5050     POL     DOUBLE SIDE BUFFER
5250     POL     ACCUMULATION
5300     POL     FINAL POLISHER
5350     CLN     POST POLISH CLEANER
ABove is the DLL for the table and its mock data.
Sample output should be like below; where when no data found in sample data 1, it will return '0'
RW_OPER     RW_AREA_GRP RW_OPER_NAME     PROC_OUT     RW_QTY
3000     MOD     ROD MOUNT     481     1248
3100     MOD     WIRE SAW     214     324
3200     MOD     AS-CUT CLEANER     642     133
3250     MOD     BEAM REMOVAL     291     357
4400     POL     ESE-II          0 424
4500     POL     EDGE OXIDE STRIP     0     821
4600     POL     LTO INSPECTION     0     909
5050     POL     DOUBLE SIDE BUFFER     0     689
5250     POL     ACCUMULATION     519     2472
5300     POL     FINAL POLISHER     439     53
5350     CLN     POST POLISH CLEANER     476     166
mY current output is below; only return record that have match to all table.
RW_OPER     RW_AREA_GRP     RW_OPER_NAME     PROC_OUT     RW_QTY
3000     MOD     ROD MOUNT     481     1248
3100     MOD     WIRE SAW     214     324
3200     MOD     AS-CUT CLEANER     642     133
3250     MOD     BEAM REMOVAL     291     357
5250     POL     ACCUMULATION     519     2472
5300     POL     FINAL POLISHER     439     53
5350     CLN     POST POLISH CLEANER     476     166
Really appreciate your response, sorry for taking time to reply.
Thanks in advance :)