Alternative to join

Question

I have got a query which is a join of 6 queries. Is there an option to replace the join? The db version is 9.2.0.1.0.

Answer 1

Sorry for not giving more info.. that was not intentional.
I had considered the union all option, but there is a possibility for duplicate records which is not desired.
Please find the query below:
SELECT /*+RULE */ -- PEWs
mc.case_type TYPE,
     c.objid c_objid,
     c.x_embargo_id embargo_id,
     c.x_tech_type embargo_tech_type,
     c.x_description,
     c.x_risk emb_cause,
     c.x_locn_node node_order,
     c.x_loctn_1141 x_code_1141,
     mc.X_CODE_1141 loc_A,
     NULL loc_b,
     mc.x_node_a,
     mc.x_node_b,
c.x_period_start x_break_start,
     c.x_period_end x_break_end,
     mc.case_type case_type,
     mc.x_pew_domain tech_type,
     mc.id_number caseid,
     mc.id_number PEWid,
x_start_dt pew_start,
     NVL(DECODE(TO_CHAR(mc.X_END_DT, 'yyyy'),'1753',NULL,
                              TO_CHAR(mc.X_END_DT,'dd/mm/rr hh24:mi')),'-') pew_end,
     mc.TITLE root_cause,
     'P' clause
FROM manis_case mc, table_x_pew_control c
WHERE mc.case_victim2case IS NULL -- either Simple PEW or SubPEW
AND mc.x_pew_domain LIKE DECODE(c.x_tech_type,'Any','%',c.x_tech_type||'%')
AND mc.x_pew_domain NOT IN('Cable','Transmission')
AND mc.x_node_a LIKE DECODE(c.x_locn_node,'ANY','%',c.x_locn_node||'%')
AND     c.x_period_end >= mc.X_START_DT
AND     mc.X_END_DT NOT BETWEEN SYSDATE-36500 AND c.x_period_start
AND c.x_period_end > SYSDATE
AND c.X_ACTIVE = 'Y'
AND mc.status NOT LIKE 'C%'
AND SUBSTR(mc.x_pew_domain,1,2) != 'ZZ'
UNION
SELECT /*+RULE */ -- Subcases
'Subcase' TYPE,
     sc.objid c_objid,
     c.x_embargo_id embargo_id,
     c.x_tech_type embargo_tech_type,
     c.x_description,
     c.x_risk emb_cause,
     c.x_locn_node node_order,
     c.x_loctn_1141 x_code_1141,
     mc.X_WM_NODEIDENT1141 loc_A,
     NULL loc_b,
     sc.x_node_a,
     sc.x_node_b,
c.x_period_start x_break_start,
     c.x_period_end x_break_end,
     sc.case_type case_type,
     sc.x_pew_domain tech_type,
     mc.id_number caseid,
     mc.id_number PEWid,
X_WMR_EXPECTEDSTART pew_start,
     NVL(DECODE(TO_CHAR(mc.X_WMR_EXPECTEDFINISH, 'yyyy'),'1753',NULL,
                              TO_CHAR(mc.X_WMR_EXPECTEDFINISH,'dd/mm/rr hh24:mi')),'-') pew_end,
     mc.TITLE root_cause,
     'C' clause
FROM manis_case sc, manis_subcase mc, table_x_pew_control c
WHERE sc.objid = mc.subcase2case
AND sc.X_PEW_DOMAIN LIKE NVL(DECODE(c.X_TECH_TYPE,'Any','%',c.x_tech_type)||'%','%')
AND( sc.x_node_a LIKE NVL(DECODE(c.x_locn_node,'ANY','%',c.x_locn_node)||'%','%')
-- better to check subcase node
OR sc.x_node_b LIKE NVL(DECODE(c.x_locn_node,'ANY','%',c.x_locn_node)||'%','%') )
-- better to check subcase node
AND     c.x_period_end >= mc.X_WMR_EXPECTEDSTART
AND     c.x_period_start <= mc.X_WMR_EXPECTEDFINISH
AND c.x_period_end > SYSDATE
AND c.X_ACTIVE = 'Y'
AND mc.status NOT LIKE 'C%'
AND SUBSTR(sc.x_pew_domain,1,2) != 'ZZ'
UNION
SELECT /*+RULE */ -- Plant continuous
x_plnt_break TYPE,
     c.objid c_objid,
     c.x_embargo_id embargo_id,
     c.x_tech_type embargo_tech_type,
     c.x_description,
     c.x_risk emb_cause,
     c.x_locn_node node_order,
     c.x_loctn_1141 x_code_1141,
     p.x_plnt_a_end loc_A,
     p.x_plnt_b_end loc_b,
     p.x_plnt_a_node x_node_a,
     p.x_plnt_b_node x_node_b,
c.x_period_start x_break_start,
     c.x_period_end x_break_end,
     mc.case_type case_type,
     mc.x_pew_domain tech_type,
     mc.id_number caseid,
     mc.id_number PEWid,
p.x_plnt_start pew_start,
     NVL(DECODE(TO_CHAR(p.x_plnt_end, 'yyyy'),'1753',NULL,
                              TO_CHAR(p.x_plnt_end,'dd/mm/rr hh24:mi')),'-') pew_end,
     mc.title root_cause,     
     '-' clause
FROM manis_case mc, table_x_plant p, table_x_pew_control c
WHERE p.x_plnt_break NOT LIKE'M%'
AND mc.objid = p.x_plant2case
AND mc.x_pew_domain LIKE NVL(DECODE(c.x_tech_type,'Any','%',c.x_tech_type)||'%','%')
AND( p.x_plnt_a_node LIKE NVL(DECODE(c.x_locn_node,'ANY','%',c.x_locn_node)||'%','%')
OR p.x_plnt_b_node LIKE NVL(DECODE(c.x_locn_node,'ANY','%',c.x_locn_node)||'%','%') )
AND     c.x_period_end >= p.x_plnt_start
AND     c.x_period_start <= p.x_plnt_end
AND c.x_period_end > SYSDATE
AND c.X_ACTIVE = 'Y'
AND mc.status NOT LIKE 'C%'
AND SUBSTR(mc.x_pew_domain,1,2) != 'ZZ'
UNION
SELECT /*+RULE */ -- Plant momentary break
x_plnt_break TYPE,
     c.objid c_objid,
     c.x_embargo_id embargo_id,
     c.x_tech_type embargo_tech_type,
     c.x_description,
     c.x_risk emb_cause,
     c.x_locn_node node_order,
     c.x_loctn_1141 x_code_1141,
     p.x_plnt_a_end loc_A,
     p.x_plnt_b_end loc_b,
     p.x_plnt_a_node x_node_a,
     p.x_plnt_b_node x_node_b,
c.x_period_start x_break_start,
     c.x_period_end x_break_end,
     mc.case_type case_type,
     mc.x_pew_domain tech_type,
     mc.id_number caseid,
     mc.id_number PEWid,
p.x_plnt_start pew_start,
     NVL(DECODE(TO_CHAR(p.x_plnt_end, 'yyyy'),'1753',NULL,
                              TO_CHAR(p.x_plnt_end,'dd/mm/rr hh24:mi')),'-') pew_end,
     mc.title root_cause,
     '&' clause
FROM manis_case mc, table_x_plant p, table_x_pew_control c
WHERE p.x_plnt_break LIKE 'M%'
AND ( (x_plnt_start BETWEEN c.x_period_start AND c.x_period_end)
OR(x_plnt_end BETWEEN c.x_period_start AND c.x_period_end) )
AND mc.objid = p.x_plant2case
AND mc.x_pew_domain LIKE NVL(DECODE(c.x_tech_type,'Any','%',c.x_tech_type)||'%','%')
AND( p.x_plnt_a_node LIKE NVL(DECODE(c.x_locn_node,'ANY','%',c.x_locn_node)||'%','%')
OR p.x_plnt_b_node LIKE NVL(DECODE(c.x_locn_node,'ANY','%',c.x_locn_node)||'%','%') )
AND     c.x_period_end >= p.x_plnt_start
AND     c.x_period_start <= p.x_plnt_end
AND c.x_period_end > SYSDATE
AND c.X_ACTIVE = 'Y'
AND mc.status NOT LIKE 'C%'
AND SUBSTR(mc.x_pew_domain,1,2) != 'ZZ'
-- Added 23/03/06 for NSI-PEWD Plant ----------------------
UNION
SELECT /*+RULE */ -- NSI-PEWD Plant continuous
p.break_col TYPE,
     c.objid c_objid,
     c.x_embargo_id embargo_id,
     c.x_tech_type embargo_tech_type,
     c.x_description,
     c.x_risk emb_cause,
     c.x_locn_node node_order,
     c.x_loctn_1141 x_code_1141,
     p.a_end_col loc_A,
     p.b_end_col loc_b,
     p.x_plnt_a_node x_node_a,
     p.x_plnt_b_node x_node_b,
c.x_period_start x_break_start,
     c.x_period_end x_break_end,
     mc.case_type case_type,
     mc.x_pew_domain tech_type,
     mc.id_number caseid,
     mc.id_number PEWid,
p.start_date_col pew_start,
     NVL(DECODE(TO_CHAR(p.end_date_col, 'yyyy'),'1753',NULL,
                              TO_CHAR(p.end_date_col,'dd/mm/rr hh24:mi')),'-') pew_end,
     mc.title root_cause,
     '-' clause
FROM manis_case mc, ew_plant_services p, table_x_pew_control c
WHERE p.separator_col = '-'
AND p.id_number = mc.id_number
AND mc.x_pew_domain LIKE DECODE(c.x_tech_type,'Any','%',c.x_tech_type||'%')
AND( p.x_plnt_a_node LIKE DECODE(c.x_locn_node,'ANY','%',c.x_locn_node||'%')
OR p.x_plnt_b_node LIKE DECODE(c.x_locn_node,'ANY','%',c.x_locn_node||'%') )
AND     c.x_period_end >= p.start_date_col
AND     c.x_period_start <= p.end_date_col
AND c.x_period_end > SYSDATE
AND c.X_ACTIVE = 'Y'
AND mc.status NOT LIKE 'C%'
AND SUBSTR(mc.x_pew_domain,1,2) != 'ZZ'
UNION
SELECT /*+RULE */ -- NSI-PEWD Plant momentary break
p.break_col TYPE,
     c.objid c_objid,
     c.x_embargo_id embargo_id,
     c.x_tech_type embargo_tech_type,
     c.x_description,
     c.x_risk emb_cause,
     c.x_locn_node node_order,
     c.x_loctn_1141 x_code_1141,
     p.a_end_col loc_A,
     p.b_end_col loc_b,
     p.x_plnt_a_node x_node_a,
     p.x_plnt_b_node x_node_b,
c.x_period_start x_break_start,
     c.x_period_end x_break_end,
     mc.case_type case_type,
     mc.x_pew_domain tech_type,
     mc.id_number caseid,
     mc.id_number PEWid,
p.start_date_col pew_start,
     NVL(DECODE(TO_CHAR(p.end_date_col, 'yyyy'),'1753',NULL,
                              TO_CHAR(p.end_date_col,'dd/mm/rr hh24:mi')),'-') pew_end,
     mc.title root_cause,
     '&' clause
FROM manis_case mc, ew_plant_services p, table_x_pew_control c
WHERE NVL(p.separator_col,'&') = '&'
AND p.id_number = mc.id_number
AND ( (start_date_col BETWEEN c.x_period_start AND c.x_period_end)
OR(end_date_col BETWEEN c.x_period_start AND c.x_period_end) )
AND mc.x_pew_domain LIKE NVL(DECODE(c.x_tech_type,'Any','%',c.x_tech_type)||'%','%')
AND( p.x_plnt_a_node LIKE NVL(DECODE(c.x_locn_node,'ANY','%',c.x_locn_node)||'%','%')
OR p.x_plnt_b_node LIKE NVL(DECODE(c.x_locn_node,'ANY','%',c.x_locn_node)||'%','%') )
AND c.x_period_end > SYSDATE
AND c.X_ACTIVE = 'Y'
AND mc.status NOT LIKE 'C%'
AND SUBSTR(mc.x_pew_domain,1,2) != 'ZZ'
ORDER BY embargo_id,PEWid,pew_start,clause DESC;