如何避免这个SQL语句的全表扫描
Select 1 from fexpense e,

fconsign c,

csubchargeitem s,

ccustsuppview csv,

cuser cu1,

cuser cu2

where (e.fexp_creator = ？ or exists (select f.FCSG_CONSIGN_ID from FCONSIGN f where f.fcsg_consign_id=e.fexp_consign_id and f.fcsg_creator = : "SYS_B_04 "))
and e.fexp_consign_id = c.fcsg_consign_id(+)

and e.fexp_charge_id = s.csci_ci_id(+)

and e.fexp_settlerment_object = csv.accountNumber(+)

and c.fcsg_creator = cu1.cusr_user_id(+)

and c.fcsg_canvasser = cu2.cusr_user_id(+)

and (e.fexp_forward_flag > ？ or e.fexp_forward_flag < ？)

and (e.fexp_cancel_flag > ？or e.fexp_cancel_flag < ？)

and (e.fexp_lump_flag > ？or e.fexp_lump_flag < ？)

and e.fexp_org_id = ？

order by e.fexp_settlerment_object ASC, e.fexp_currency_code ASC

看了执行计划，提示fexpense表做了全表扫描，我对该表的WHERE条件中的字段做了个联合索引，还是提示全表，有什么解决办法

[解决办法]
exist结果就全是真的，估计你想要的是
(e.fexp_creator = ？ or e.fexp_creator in (select f.FCSG_CONSIGN_ID from FCONSIGN f where f.fcsg_creator = : "SYS_B_04 "))
这样，就会用fexpense的fexp_creator索引了

[解决办法]
Analyze Table fexpense compute Statistics; ---更新数据统计

alter index index_name rebuild; -----如果索引没有生效则重编译

因为oracle的优化器默认是按照choose 的，而不是基于规则的。