GROUP_CONCAT 增加序号

SELECT
    group_concat(
    concat(
    @j :=
IF
    ( @p = s.semester_id, @j + 1, IF ( @p := s.semester_id, 1, 1 ) ),
    '.',
    s.item 
    ) SEPARATOR ', ' 
    ) FirstName,
    s.* 
FROM
    scd_cost_charge_item s 
WHERE
    s.sys_state = 0 
GROUP BY
    s.semester_id;