SQL Server - 从名称列表中获取首字母

Question

我有一个表格，其中包含分配给某个项目的员工列表。 有点像这样：

ID  Employees
122 Mark Doe
210 John Doe
212 Julie Doe, Yuri Doe

我必须转换“雇员”列以获取名字的首字母并获取完整的姓氏。 结果应该是这样的：

ID  Employees
122 M. Doe
210 J. Doe
212 J. Doe, Y. Doe

当值包含多个名称时会出现问题。 为此可以做些什么？

Answer 1

PostgreSQL 的解决方案。 假设单元格中的多个名称始终由逗号和后面的空格分隔，您可以

1 将所有多名称单元格展开成单独的行
2 将带有名称的列拆分为代表名字和姓氏的单独列
3 从名字中提取第一个字母并将其与姓氏连接

CREATE TABLE employees (id int, employee VARCHAR(50))
INSERT INTO employees (id, employee)
VALUES 
(122, 'Mark Doe'),
(210, 'John Doe'),
(212, 'Julie Doe, Yuri Doe');
 
 SELECT
 id
 ,left(split_part(firs_last_name,' ',1),1) || '. ' || split_part(firs_last_name,' ',2) 
 as  wanted_name
 ,split_part(firs_last_name,' ',1) as first_name
 ,split_part(firs_last_name,' ',2) as last_name
 FROM
   (
   Select 
   id, unnest(string_to_array(employee, ', ')) as firs_last_name
    FROM employees
   ) s

|  id | wanted_name | first_name | last_name |
|-----|-------------|------------|-----------|
| 122 |      M. Doe |       Mark |       Doe |
| 210 |      J. Doe |       John |       Doe |
| 212 |      J. Doe |      Julie |       Doe |
| 212 |      Y. Doe |       Yuri |       Doe |

如果您想在单元格中恢复多个名称，您可以在最后一步中将它们聚合

CREATE TABLE employees (id int, employee VARCHAR(50))
INSERT INTO employees (id, employee)
VALUES 
(122, 'Mark Doe'),
(210, 'John Doe'),
(212, 'Julie Doe, Yuri Doe');
 
 with transformed_names as 
 (SELECT
 id
 ,left(split_part(firs_last_name,' ',1),1) || '. ' || 
  split_part(firs_last_name,' ',2)  as  wanted_name
 ,split_part(firs_last_name,' ',1) as first_name
 ,split_part(firs_last_name,' ',2) as last_name
 FROM
   (
   Select 
   id ,unnest(string_to_array(employee, ', ')) as firs_last_name
   FROM employees
   ) s)

SELECT
id
, string_agg(wanted_name, ', ') as wanted_names  
from transformed_names
GROUP BY 
id

|  id |     string_agg |
|-----|----------------|
| 122 |         M. Doe |
| 210 |         J. Doe |
| 212 | J. Doe, Y. Doe |

但话又说回来，这一切都取决于表中干净一致的数据