UC知道帮我整体分析和讲解下以下 SQL语句（ORACLE中的），给50分~~~
来源：百度知道 编辑：UC知道 时间：2024/06/24 14:23:51
select c.dsc 订货方式,count(distinct a.orderid) 订单总数,d.orid 成功订单总数,h.gnum 成功订货款
,decode(count(distinct a.orderid),0,0,to_char(d.orid/count(distinct a.orderid),'0D999')) 订单成功率
from orderhist a,names c, orderdet y,
(select f.dsc fdsc,COUNT(distinct e.orderid) orid from orderhist e,names f,orderdet x
where e.orderid=x.orderid and e.status = '5' and e.mailtype = f.id and f.TID = 'BUYTYPE'
and trunc(e.crdt) between to_date('^1','yyyy-mm-dd') and to_date('^2','YYYY-MM-DD')
and x.soldwith in ('1','2','3')
--and e.ordertype in (select id from names where tid = 'ORDERTYPE' and dsc = '^3')
group by f.dsc) d,
(select f.dsc hdsc, sum(g.uprice*g.upnum + g.sprice * g.spnum) gnum
from orderhist e,names f,orderdet g
,decode(count(distinct a.orderid),0,0,to_char(d.orid/count(distinct a.orderid),'0D999')) 订单成功率
from orderhist a,names c, orderdet y,
(select f.dsc fdsc,COUNT(distinct e.orderid) orid from orderhist e,names f,orderdet x
where e.orderid=x.orderid and e.status = '5' and e.mailtype = f.id and f.TID = 'BUYTYPE'
and trunc(e.crdt) between to_date('^1','yyyy-mm-dd') and to_date('^2','YYYY-MM-DD')
and x.soldwith in ('1','2','3')
--and e.ordertype in (select id from names where tid = 'ORDERTYPE' and dsc = '^3')
group by f.dsc) d,
(select f.dsc hdsc, sum(g.uprice*g.upnum + g.sprice * g.spnum) gnum
from orderhist e,names f,orderdet g
select: 查询
c.dsc 订货方式: c表的dsc字段 显示字段名字为 订货方式
count（）：聚合函数 统计数量的
distinct ：消除重复的
from orderhist a,names c, orderdet y：要查询的表 orderhist表在这条语句中命名为a
where ：条件
between and :在这2个时间内
x.soldwith in ('1','2','3')：x表soldwith 字段的值是1 2 3的
group by ：分组显示
sum（）：聚合函数 字段的值的和
没什么拉逻辑 把表与表之间的关系理清就可以了
而且最后还少一个括号
1