Question

我无法根据两个条件获取所需的数据，并且我有此数据库：

library(dplyr)

before <- after <- 4
df %>%
  mutate(a = "%%0%d.%df" %>%
             sprintf(before + after + 1, after) %>% 
             sprintf(a) %>%
             chartr(".", ",", .))

我想接待所有出现在Hanoh levin Play中但没有出现在Nisim Aloni Play中的演员（在本案中，除了shir以外，请把所有演员都收起。

我尝试这样做：

          a
1 0002,5000
2 0003,5600
3 0004,5000

我得到一个错误，或者如果我稍做改动就什么也没得到。根据数据库，我不应该接受女演员Shir，因为她出演了两位导演的戏剧。我做错了什么？

谢谢

Answer 1

您可以对联接使用以下查询：

select a_name
  from Actor a
  join Role r on r.a_id = a.a_id
  join Play p on p.p_id = r.p_id 
 where exists ( select 1 from Play where director = 'Hanoh levin' and p_id = p.p_id )
   and not exists ( select 1 from Play where director = 'Nisim Aloni' and p_id = p.p_id );

A_NAME
------
Shir
Noa
Osher

Demo

Answer 2

加入3个表并按演员名称分组：

select a.a_name 
from actor a inner join role r
on r.a_id = a.a_id
inner join play p
on p.p_id = r.p_id
where p.director in ('Hanoh levin', 'Nisim Aloni')
group by a.a_name
having min(p.director) = 'Hanoh levin' and max(p.director) = 'Hanoh levin'

请参见demo
结果：

| a_name |
| ------ |
| Noa    |
| Osher  |

Answer 3

只需与主管联系即可。

select a_name from Actor a
  join Role r on r.a_id = a.a_id
  join Play p on p.p_id = r.p_id 
 where  p.director = 'Hanoh levin' 
   and p.director <> 'Nisim Aloni'

SQL-使用AND选择两个条件或多个条件

3 个答案: