1、如何查询两个不相关联的表统计总数按照比例显示
select C1||'/'||C2 from
(select count(*) as C1 from m_url) A,
(select count(*) as C2 from t_jc_diccode) B
可以将||‘/’||变为，分成一行2列，变为+算总数，变为||字符串拼接
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2、查询某一年每月月季数据统计
select sum(case when EXTRACT(MONTH FROM SIGN_STDT)=01 then 1 else 0 end) as A,
sum(case when EXTRACT(MONTH FROM SIGN_STDT)=02 then 1 else 0 end) as B,
sum(case when 提取(MONTH FROM 列名)=03 then 1 else 0 end) as C,
中间的一样我就不复制了，有加密一条要分两节复制很麻烦。
from TABLE
where SIGN_STDT
between to_date('2017/11/01','yyyy/mm/dd hh24:mi:ss')
and to_date('2017/11/30','yyyy/mm/dd hh24:mi:ss')；
//下面这个是查的所有年份为2017年的比较死一些
select sum(case when EXTRACT(MONTH FROM SIGN_STDT)=01 then 1 else 0 end) as A,
sum(case when EXTRACT(MONTH FROM SIGN_STDT)=02 then 1 else 0 end) as B,
sum(case when EXTRACT(MONTH FROM SIGN_STDT)=03 then 1 else 0 end) as C,
中间的一样我就不复制了，有加密一条要分两节复制很麻烦。
from TABLE
where EXTRACT(YEAR FROM SIGN_STDT)='2017'
//这个是老大哥写的将年月转成char类型，根据年月来统计，不过因为12个月，假如有几个月没有数据，就会不显示，所以我们公司不让用，也分享给大家
select to_char(exportDate,'yyyy/mm'),sum(1) from TABLE group by to_char(exportDate,'yyyy/mm');
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