INDEX_JOIN (TABLE INDEX_NAME) * / clear command prompt optimization index as the access path is used, for example:. SELECT / * INDEX_JOIN (BSEMPMS SAL_HMI HIREDATE_BMI) * / SAL, HIREDATEFROM BSEMPMS WHERE SAL <60000; 12. / * INDEX_DESC (TABLE INDEX_NAME ) * / Indicate the scanning method for the index descending sequence. For example: select / * index_desc (bsempms pk_bsempms) * / from bsempms where dpt_no = 'scott'; 13. / * index_name * / to specified The table performs a fast full index scan, not a full metric scan. For example: select / * index_ffs (bsempms in_empnam) * / * from bsempms where dpt_no = 'TEC305'; 14. / * add_equal table index_nam1, index_nam2 ,. .. * / Tip Clearly perform the selection of the planning, the scanning of several single colony indexes. For example: SELECT / * INDEX_FFS (bsempms in_DPTNO, IN_EMPNO, IN_SEX) * / * from bsempms where EMP_NO = 'Scott' and DPT_NO = 'TDC306'; 15. / * USE_CONCAT * / Converts the OR condition behind the WHER in the query to the combination query of Union All. For example: SELECT / * USE_CONCAT * / * from bsempms where dpt_no = 'TDC506' AND SEX = 'm'; 16. / * no_expand * / For or in-list of WHERE or in-list, no_expand will prevent it from extension based on the optimizer. For example: SELECT / * NO_EXPAND * / * FROM Bsempms where dpt_no = 'tdc506' and sex = 'm'; 17. / * NOWRITE * / Do not prohibit query override the query block. 18. / * Rewrite * / You can use the view as a parameter. 19. / * Merge (Table) * / Ability to merge the respective queries of the view. For example: S ELECT / * MERGE (V) * / a.emp_no, a.emp_nam, b.dpt_no from bsempms A (Selet DPT_NO, AVG (SAL) AS AVG_SAL FROM BSEMPMS B Group BY DPT_NO) V where a.dpt_no = v.dpt_noand A.SAL> V.AVG_SAL; 20. / * No_merge (Table) * / For a mergeable view no longer merged. For example: SELECT / * NO_MERGE (V) * / a.emp_no, a.emp_nam, b .Dpt_no from bsempms A (SELECT DPT_NO, AVG (SAL) AS AVG_SAL from BSempms B Group By DPT_NO) V where a.dpt_no = v.dpt_no and a.sal> v.avg_sal; 21. / * Ordered * / according to Table The order in from From, Ordered makes Oracle to this sequence. For example: select / * ordered * / a.col1, b.col2, c.col3 from table1 a, table2 b, table3 c where a.col1 =
