如何将多个列值连接成一个列？

Question

我有以下table朋友

id | first_name | last_name | gender | age | mobile
1  | bobby      | roe       | male   | 21  | 541-5780

如何将多列 (first_name 和 last_name) 值连接到一列中以获得以下结果？

full_name
bobby roe

我已经编写了以下查询，但它不起作用

declare @full_name varchar(max)
select @full_name = COALESCE(@full_name + ', ', '') + first_name, last_name
from friend
select @full_name

Answer 1

实现此目的的方法不止一种：

SELECT CONCAT(first_name, ' ' ,last_name) AS full_name;

对于早期版本（其中 CONCAT 不是内置函数）：

SELECT first_name + ISNULL(' ' + last_name, '') as Full_Name from [YourTable]

这也应该给你同样的结果

SELECT COALESCE(first_name, '') + COALESCE(last_name, '') as FullName FROM [YourTable]

how to concatenate multiple column values into a single column?