[递归]可能会用到

WITH
    RECURSIVE cteTree AS
    (
        SELECT
            pc.id,
            pc.parent_id,
            pc.name,
            CONCAT(pc.id,'') AS nodePath,
            1                   lev
        FROM
            product_category pc
        WHERE
            id = 1
        UNION ALL
        SELECT
            pc1.id,
            pc1.parent_id,
            pc1.name,
            CONCAT(c.nodePath,'/',pc1.id) AS nodePath,
            c.lev +                          1
        FROM
            cteTree c
        INNER JOIN
            product_category pc1
        ON
            pc1.parent_id = c.id
    )
--SELECT split_part(nodePath,'/',2) as id FROM cteTree
SELECT
    *
FROM
    cteTree