ALTER TABLE t_life_event
    ADD COLUMN time_mode VARCHAR(20) DEFAULT 'date' COMMENT '时间模式: date-具体日期, month-年月, season-季节, range-时间范围' AFTER event_date,
    ADD COLUMN event_date_text VARCHAR(50) COMMENT '原始时间文本' AFTER time_mode,
    ADD COLUMN event_end_date DATETIME COMMENT '结束日期，仅时间范围使用' AFTER event_date_text;

UPDATE t_life_event
SET time_mode = COALESCE(time_mode, 'date'),
    event_date_text = COALESCE(event_date_text, DATE_FORMAT(event_date, '%Y-%m-%d'))
WHERE is_deleted = 0;