如何优化我的 oracle sql？答案

【问题标题】：how to optimize my oracle sql?如何优化我的 oracle sql？
【发布时间】：2017-12-19 00:44:57
【问题描述】：

我需要在两个日期范围内计数，这个 sql 可以工作，bug 不是更好，你能帮帮我吗？

select dmc.doctor_id,
(
    select count(*)
    from hele_dct_member_config dmc
    WHERE (EXTRACT(YEAR FROM dmc.start_time) = 2016 OR EXTRACT(YEAR FROM dmc.end_time) = 2016) AND dmc.status=1
    AND TO_DATE('2016-01-31', 'yyyy-mm-dd') BETWEEN start_time AND end_time
) Jan,
(
    select count(*)
    from hele_dct_member_config dmc
    WHERE (EXTRACT(YEAR FROM dmc.start_time) = 2016 OR EXTRACT(YEAR FROM dmc.end_time) = 2016) AND dmc.status=1
    AND TO_DATE('2016-02-28', 'yyyy-mm-dd') BETWEEN start_time AND end_time
) Feb,
.
.
.
from hele_dct_member_config dmc
enter code here
WHERE (EXTRACT(YEAR FROM dmc.start_time) = 2016 OR EXTRACT(YEAR FROM dmc.end_time) = 2016) AND dmc.status=1
grouy by dmc.doctor_id

我需要在两个日期范围内计数，这个 sql 可以工作，bug 不是更好，你能帮帮我吗？

【问题讨论】：

标签： sql oracle conditional-aggregation

【解决方案1】：

使用条件聚合：

select dmc.doctor_id,
       sum(case when date '2016-01-31' BETWEEN start_time AND end_time then 1 else 0
           end) as Jan,
       sum(case when date '2016-02-31' BETWEEN start_time AND end_time then 1 else 0
           end) as Feb,
    .
    .
    .
from hele_dct_member_config dmc
where (extract(year from dmc.start_time) = 2016 or
       extract(year from dmc.end_time) = 2016) AND
      dmc.status = 1
group by dmc.doctor_id;

【讨论】：

【解决方案2】：

如果我想得到季度数？这是一种方式

   SUM(case when date '2016-01-31' BETWEEN start_time AND end_time then 1 else 0 end) + 
   SUM(case when date '2016-02-28' BETWEEN start_time AND end_time then 1 else 0 end) + 
   SUM(case when date '2016-03-31' BETWEEN start_time AND end_time then 1 else 0 end)  one

【讨论】：