select c.tskillgrp_code, nvl(sum(case when b.composite_timeout='0' and b.handle_timeout = '0' and b.reply_timeout = '0' and b.archive_timeout = '0' then 1 end),0) notTimeoutCount,nvl(sum(case when b.composite_timeout = '1' then 1 else 0 end),0) compositeCount,nvl(sum(case when b.handle_timeout = '1' then 1 else 0 end),0) handleCount,nvl(sum(case when b.sreply_timeout = '1' then 1 else 0 end),0) replyCount,nvl(sum(case when b.archive_timeout = '1' then 1 else 0 end),0) archiveCount,nvl(count(t.case_no),0) allCount from table_one t,table_two b,table_three c where t.case_no = b.case_no and t.case_no = c.case_no and c.deal_flag = '3' group by c.tskillgrp_code
每个表中都有三百万以上的数据，所以关联查询起来相当慢，所以请帮忙优化一下，谢谢！
------解决方案--------------------
- JScript code
select c.tskillgrp_code, nvl(sum(case when b.composite_timeout = '0' and b.handle_timeout = '0' and b.reply_timeout = '0' and b.archive_timeout = '0' then 1 end), 0) notTimeoutCount, nvl(sum(case when b.composite_timeout = '1' then 1 else 0 end), 0) compositeCount, nvl(sum(case when b.handle_timeout = '1' then 1 else 0 end), 0) handleCount, nvl(sum(case when b.sreply_timeout = '1' then 1 else 0 end), 0) replyCount, nvl(sum(case when b.archive_timeout = '1' then 1 else 0 end), 0) archiveCount, nvl(count(t.case_no), 0) allCount from table_one t, table_two b, table_three c where t.case_no = b.case_no and t.case_no = c.case_no and c.deal_flag = '3' group by c.tskillgrp_code
------解决方案--------------------
额，表的索引页不经建太多，建多了也影响查询速度的。
- SQL code
select d.tskillgrp_code, sum(notTimeout) notTimeoutCount, sum(composite) compositeCount, sum(handleCount) handleCount, sum(reply) replyCount, sum(archive) archiveCount, count(t.case_no) allCount from (select c.tskillgrp_code, case when b.composite_timeout = '0' and b.handle_timeout = '0' and b.reply_timeout = '' 0 '' and b.archive_timeout = '' 0 '' then 1 end notTimeout, case when b.composite_timeout = '1' then 1 else 0 end composite, case when b.handle_timeout = '' 1 '' then 1 else 0 end handle, case when b.sreply_timeout = '' 1 '' then 1 else 0 end reply, case when b.archive_timeout = '1' then 1 else 0 end archive, t.case_no from table_one t, table_two b, table_three c where t.case_no = b.case_no and t.case_no = c.case_no and c.deal_flag = '3') d group by d.tskillgrp_code