for xml path 与 group_concat 与 WM_CONCAT，多字段合并成一行数据

-- sql server，自定义用逗号分割
SELECT
    id,
    psn = (stuff (( SELECT ',' + realname FROM staff_tbl WHERE psn = 'c0c2c19c-9bb4-11e8-9d65-000c2964' FOR XML path ( '' ) ),1,1,'')) 
FROM
    staff_tbl a 
GROUP BY
    id

--  group_concat(),默认逗号分隔
SELECT
    id,
    psn,
    ( SELECT group_concat( realname ) FROM staff_tbl WHERE psn = 'c0c2c19c-9bb4-11e8-9d65-000c2964' ) AS myIdea 
FROM
    staff_tbl 
GROUP BY
    id;
    
-- 空格分割
SELECT
    GROUP_CONCAT( realname SEPARATOR ' ' ) AS myIdea 
FROM
    staff_tbl 
WHERE
    psn = 'c0c2c19c-9bb4-11e8-9d65-000c2964';
    
-- Oracle  ，函数不一定可用
SELECT
    WM_CONCAT ( realname ) AS myIdea 
FROM
    staff_tbl

SELECT REPLACE
    ( SELECT WM_CONCAT ( realname ) AS myIdea FROM staff_tbl, ',', '|' ) 
FROM
    staff_tbl;