PostgreSQL error:recursive Query "T" column 2 has type character varying ($) in non-recursive term but type character VA Rying overall

Recently, when doing a project, there is a need to find out the current logged in the user's jurisdiction over all areas of the data, and the query of the Department information in the following format to show

Supreme People's Court > Jiangsu Provincial Higher courts > Nantong Intermediate Court
Supreme People's Court > Jiangsu Provincial Higher courts > Lianyungang Intermediate Court

, then query with the following statement

 
 
WITH RECURSIVE T AS (
    SELECT
        c_id,
        c_name
    FROM
        db_aty.t_aty_corp
    WHERE
        c_pid IS NULL
    UNION ALL
        SELECT
            D.c_id,
            T.c_name || ‘>‘ || D.c_name
        FROM
            db_aty.t_aty_corp D
        JOIN T ON D.c_pid = T .c_id
) SELECT
    c_id AS corpId,
    c_name AS corpName
FROM
    T

However, the following error occurred

error:recursive query "T" column 2 has type character varying ($) in non-recursive term but type character varying over All

Guess this is because the use of union ALL in an SQL statement requires the same field properties that are queried before and after the query, using T.c_name | | ' > ' | | D.c_name is a concatenation of strings, so the field properties are associated with the previous

C_name inconsistent, so cause error,

Workaround: Specify the field format for the stitched string

 
 
WITH RECURSIVE T  AS (
    SELECT
        c_id,
        c_name::varchar(150)
    
    FROM
        db_aty.t_aty_corp
    WHERE
        c_pid is null
    UNION ALL
        SELECT
            D.c_id,
            (T.c_name   || ‘>‘ || D.c_name )::varchar(150) as c_name
        FROM
            db_aty.t_aty_corp D
        JOIN T ON D.c_pid = T .c_id
) 
SELECT c_id AS corpId ,c_name as corpName  FROM T

Get the correct answer as follows

PostgreSQL error:recursive Query "T" column 2 has type character varying ($) in non-recursive term but type character VA Rying overall