.... -- ============================================================ -- Table: XXX -- ============================================================ create table XXX ( USER_ID INTEGER not null , LOCALE_ID INTEGER not null , CREATE_BY VARGRAPHIC(60) ...
我看ocp 教材上写bitmap index efficient for queries using or predicates. 可是我怎么也想不明白为什么?那位大哥能解释一下. 我在线等!!!!!!!!!
各位好,我是一位新手,希望得到大家的帮助。 在测试index命令时,有一点不解,例: #!/usr/bin/perl -w index " a boy","boy"; 执行后提示: useless use of index in void context at ii.pl line 2. 这里上下文怎么是无效? 求解,谢谢!
IF my sql query does not know how to pick up the index which i created earlier then what should i do???
I wish to know how I going to know am I create a correct index? Can any provide some examples for creating a proper index? THANKS...
select acct_id,sum(charge) from acct_item where acct_id in ( select acct_id from tmp_62) and state in ('20C','20T') group by acct_id; 这个语句如果不加任何提示不会用上索引,执行得很慢。 SELECT /*+ index(acct_item,idx_acct_item_acct) */ acct_id, SUM (charge) FROM acct_item WHERE acct_id IN ( SELECT acct_id FROM tmp_62) AND state IN ('20C', '20T') GROUP BY acct_id 如果加了索引提示就能使用...
下面这个语句如果不加任何提示不会用上索引,执行得很慢 。 select acct_id,sum(charge) from acct_item where acct_id in ( select acct_id from tmp_62) and state in ('20C','20T') group by acct_id; 如果加了索引提示就能使用索引,执行得很快。 SELECT /*+ index(acct_item,idx_acct_item_acct) */ acct_id, SUM (charge) FROM acct_item WHERE acct_id IN ( SELECT acct_id FROM tmp_62) AND state IN ('20C', '2...