sql - 如果 id 匹配，SQL 从第二个表中选择日期

Question

我有两张表 Security 和 CallPut。安全性（table1）包含security_id和mature_date（非noll值）和CallPut（table2），它具有security_id和Odate（它们是包含日期时间格式值的非空值）我想从security（表1）中选择所有行但在成熟日期我想要来自 odate 列的值而不是成熟日期，其中安全 id 存在于 Callput(table2) 中并与安全表匹配

例如安全(table1)

Security_id|Maturity_date
abcd        25Jan2020
bcde        25jan2021 

调用（表2）

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)

我用oracle sql 请帮忙。提前致谢

Answer 1

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 2

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

未经测试，但您想使用联接。您可以在http://docs.oracle.com/cd/B28359_01/server.111/b28286/queries006.htm了解有关 Oracle 大量文档的更多信息

Answer 3

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

ps 刚刚注意到这是一个 Oracle 问题，我的代码适用于 MS SQL Server
编辑：针对 Oracle 语法进行了更正。