pgsql多行合併方法,將結果返回爲逗號分隔的列表

--公式

STRING_AGG(expression, separator)

　　

CREATE TABLE employees (
    id SERIAL PRIMARY KEY,
    name VARCHAR(50),
    department VARCHAR(50)
);

INSERT INTO employees (name, department) VALUES
    ('John', 'Sales'),
    ('Jane', 'HR'),
    ('David', 'Finance'),
    ('Sarah', 'Sales');

　　

SELECT department, STRING_AGG(name, ',') AS employees_list
FROM employees
GROUP BY department;
SQL
上述查詢將返回類似於以下結果：

  department  |   employees_list   
--------------+--------------------
 Sales        | John,Sarah
 HR           | Jane
 Finance      | David

借鑑地址：https://deepinout.com/sql/sql-questions/76_sql_postgresql_query_to_return_results_as_a_comma_separated_list.html