sql - SQL如何在2列之间找到第一个非空值

Question

给定两张表

partner

ID | name
----------
 1 | NULL
 2 |  bob
 3 |  C
 4 | tom

partner  history 
ID | name
----------
 1 | joe
 2 |  bob
 3 |  C
 4 | NULL

我想获取列名的第一个非空值。

SELECT ???? as name FROM partner p  FULL JOIN partner_history ph ON p.idPartner = ph.idPartner

标签： sqlsql-server

Answer 1

使用合并：

SELECT 
    COALESCE(p.name, ph.name) as name 
FROM partner p  
FULL JOIN partner_history ph 
    ON p.idPartner = ph.idPartner