MySQL SUM 函数用于计算多条记录中某个字段的总和。要理解 SUM() 函数，请考虑一个“employee_tbl”表，该表具有以下记录 -
mysql> SELECT * FROM employee_tbl; +------+------+------------+--------------------+ | id | name | work_date | daily_typing_pages | +------+------+------------+--------------------+ | 1 | John | 2007-01-24 | 250 | | 2 | Ram | 2007-05-27 | 220 | | 3 | Jack | 2007-05-06 | 170 | | 3 | Jack | 2007-04-06 | 100 | | 4 | Jill | 2007-04-06 | 220 | | 5 | Zara | 2007-06-06 | 300 | | 5 | Zara | 2007-02-06 | 350 | +------+------+------------+--------------------+ 7 rows in set (0.00 sec)
现在，假设根据上表您想要计算所有 dialy_typing_pages 的总数，那么您可以使用以下命令来完成 -
mysql> SELECT SUM(daily_typing_pages)
-> FROM employee_tbl;
+-------------------------+
| SUM(daily_typing_pages) |
+-------------------------+
| 1610 |
+-------------------------+
1 row in set (0.00 sec)以上是我们如何使用 MySQL SUM() 函数？的详细内容。更多信息请关注PHP中文网其他相关文章！
