SQL查询的索引指南

SELECT   v.volume_id
  FROM   (  SELECT   MIN (usv.volume_id) volume_id
              FROM   user_stage_volume usv
             WHERE   usv.status = \'NEW\'
                     AND NOT EXISTS
                           (SELECT   1
                              FROM   user_stage_volume kusv
                             WHERE   kusv.deal_num = usv.deal_num
                                     AND kusv.locked = \'Y\')
          GROUP BY   usv.deal_num, usv.volume_type
          ORDER BY   MAX (usv.priority) DESC, MIN (usv.last_update) ASC) v
 WHERE   ROWNUM = 1;

CREATE TABLE ENDUR.USER_STAGE_VOLUME
(
  DEAL_NUM       NUMBER(38)                     NOT NULL,
  EXTERNAL_ID    NUMBER(38)                     NOT NULL,
  VOLUME_TYPE    NUMBER(38)                     NOT NULL,
  EXTERNAL_TYPE  VARCHAR2(100 BYTE)             NOT NULL,
  GMT_START      DATE                           NOT NULL,
  GMT_END        DATE                           NOT NULL,
  VALUE          FLOAT(126)                     NOT NULL,
  VOLUME_ID      NUMBER(38)                     NOT NULL,
  PRIORITY       INTEGER                        NOT NULL,
  STATUS         VARCHAR2(100 BYTE)             NOT NULL,
  LAST_UPDATE    DATE                           NOT NULL,
  LOCKED         CHAR(1 BYTE)                   NOT NULL,
  RETRY_COUNT    INTEGER                        DEFAULT 0 NOT NULL,
  INS_DATE       DATE                           NOT NULL
)

ALTER TABLE ENDUR.USER_STAGE_VOLUME ADD (
  PRIMARY KEY
 (VOLUME_ID))