Assume that the name of this table is tentatively demo_table
You can use the following statement to achieve your needs

SELECT
    wid,
    SUBSTRING_INDEX(GROUP_CONCAT(uid ORDER BY id),',',5) AS 'uids'
FROM demo_table
GROUP BY wid

@deepgoing’s idea is okay. In order to solve the problem of uid duplication and sorting, you can first do a distcint query, such as:

SELECT
    wid,
    SUBSTRING_INDEX(GROUP_CONCAT(uid ORDER BY id),',',5) AS 'uids'
FROM (
  SELECT DISTINCT wid, uid
  FROM demo_table
  ORDER BY wid, uid
)
GROUP BY wid