SQL 语句：按日期求和并分组显示，统计每月数据及上下旬数据

这里提供两个SQL语句实现需求：

1. 对同日期的数据求和并显示为一行，统计一个月数据求和：

SELECT date, SUM(value) AS total_value 
FROM table_name 
GROUP BY date 
ORDER BY date ASC;

2. 统计每月上下旬数据求和：

SELECT 
  DATE_FORMAT(date, '%Y-%m') AS month,
  SUM(CASE WHEN DAY(date) <= 10 THEN value ELSE 0 END) AS first_ten_total,
  SUM(CASE WHEN DAY(date) > 10 AND DAY(date) <= 20 THEN value ELSE 0 END) AS second_ten_total,
  SUM(CASE WHEN DAY(date) > 20 THEN value ELSE 0 END) AS third_ten_total,
  SUM(value) AS total
FROM table_name
GROUP BY month
ORDER BY month ASC;

注意：以上SQL语句仅供参考，具体实现可能需要根据实际情况进行修改。