SQL如果id匹配，则从第二个表中选择日期

Question

我有两个表Security和CallPut。security (table1)包含security_id和maturity_date (非NULL值)，Callput(table2)包含security_id和odate (它们是包含日期时间格式值的非NULL值)我想从security (表1)中选择所有行，但在maturity_date中，我想要Odate列中的值，而不是maturity_date，其中Security id存在于CallPut(table2)中并与security表匹配

Security_id|Maturity_date
abcd        25Jan2020
bcde        25jan2021 

Callput(tabble2)

Security_id|Odate
abcd        25Jan2015 

所需输出

Security_id|Maturity_date
abcd        25Jan2015 (since here id is there in callput it takes odate)
bcde        25jan2021 (since here id is not there in callput it takes maturity date)

提前感谢

Answer 1

select s.Security_id, nvl(c.odate, s.Maturity_date) as Maturity_date
from Security s
left join
Callput c
on
s.Security_id = c.Security_id

附注：我刚注意到这是一个Oracle问题，我的代码是针对MS SQL Server的

编辑:已针对Oracle语法进行更正。

Answer 2

select 
    s.Security_id,
    NVL(c.Odate, s.Maturity_date) Maturity_date
from 
    security s left join callput c 
    on (c.security_id = s.security_id);

Answer 3

select s.* from security as s left join callput as c on (c.security_id = s.security_id);

未测试，但您想要使用联接。您可以在http://docs.oracle.com/cd/B28359_01/server.111/b28286/queries006.htm的Oracle内容丰富的文档中了解有关连接的更多信息