这段SQL为什么不走索引?
SELECT TO_CHAR (mmt.transaction_date, 'yyyy/mm/dd') AS transaction_date,
  wdj.attribute10 AS order_number,
  wdj.attribute11 AS order_line_number, mmt.organization_id,
  mmt.inventory_item_id,
  -SUM (mtl.transaction_quantity) AS transaction_quantity,
  mmt.transaction_uom, 1 trx_type
  FROM mtl_material_transactions mmt,
  mtl_transaction_lot_numbers mtl,
  wip_discrete_jobs wdj,
  wip_entities we
  WHERE 1 = 1
  AND mmt.organization_id = mtl.organization_id
  AND mmt.transaction_id = mtl.transaction_id
  AND mmt.inventory_item_id = mtl.inventory_item_id
  AND wdj.wip_entity_id = we.wip_entity_id
  AND wdj.organization_id = mmt.organization_id
  AND wdj.primary_item_id = mmt.inventory_item_id
  AND SUBSTR (mtl.lot_number,
  INSTR (mtl.lot_number, '#', 1) + 1,
  LENGTH (mtl.lot_number)
  ) = we.wip_entity_name
  AND mmt.transaction_source_type_id = 13
  AND mmt.transaction_action_id = 2
  AND ( mmt.subinventory_code IN ('QC90', 'QC91', 'QC92')
  OR mmt.subinventory_code IN (
  SELECT DISTINCT msub.secondary_inventory_name
  FROM mtl_secondary_inventories msub
  WHERE NVL (msub.attribute2, 'abc') = 'PRD'
  AND msub.organization_id = mmt.organization_id)
  )
  AND wdj.attribute10 is not null
  AND wdj.attribute11 is not null
  AND mmt.transfer_subinventory LIKE '%88'
  GROUP BY TO_CHAR (mmt.transaction_date, 'yyyy/mm/dd'),
  wdj.attribute10,
  wdj.attribute11,
  mmt.organization_id,
  mmt.inventory_item_id,
  mmt.transaction_uom

各位大虾,这段SQL中的wip_discrete_jobs wdj表没有走索引,不知道为什么,其它几个表都走了,此表有49W数据,
建有联合索引(organization_id,wip_entity_id),单独索引primary_item_id,求救.

------解决方案--------------------
AND wdj.attribute10 is not null
AND wdj.attribute11 is not null
在进行NULL或者NOT NULL判断的时候，会进行全表检索，不会走索引
可以适当地在此做一点优化
------解决方案--------------------
具体看一下执行的计划为什么没有走索引的。或者跟踪一下语句。
------解决方案--------------------
你的索引字段作为条件查询了吗?
试下把索引字段作为条件查询下.
------解决方案--------------------
TABLE ACCESS FULL Object owner=WIP Object name=WIP_DISCRETE_JOBS Cost=5230 Cardinality=3875 Bytes=77500

明显的走了全表扫描
------解决方案--------------------

探讨

TABLE ACCESS FULL Object owner=WIP Object name=WIP_DISCRETE_JOBS Cost=5230 Cardinality=3875 Bytes=77500

明显的走了全表扫描

------解决方案--------------------
现在有个问题：楼主现在用没有走索引的语句 导致执行效率变差了，还是说没走索引不影响速度但想知道原因？
不是说走了索引速度就快
------解决方案--------------------
本身这段SQL就包含统计分组函数，结构也些许复杂，
执行笑傲率应该不会太快的