《Mysql應(yīng)用MySQL中的SUM函數(shù)使用教程》要點(diǎn)：
本文介紹了Mysql應(yīng)用MySQL中的SUM函數(shù)使用教程，希望對(duì)您有用。如果有疑問(wèn)，可以聯(lián)系我們。
MYSQL數(shù)據(jù)庫(kù)MySQL的SUM函數(shù)是用來(lái)找出記錄中各種的字段的總和.
MYSQL數(shù)據(jù)庫(kù)要了解SUM函數(shù)考慮EMPLOYEE_TBL表具有以下記錄：
MYSQL數(shù)據(jù)庫(kù)
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)
MYSQL數(shù)據(jù)庫(kù)現(xiàn)在,假設(shè)根據(jù)上面的表想來(lái)計(jì)算所有的dialy_typing_pages的總數(shù),那么可以通過(guò)使用下面的命令：
MYSQL數(shù)據(jù)庫(kù)
mysql> SELECT SUM(daily_typing_pages)
-> FROM employee_tbl;
+-------------------------+
| SUM(daily_typing_pages) |
+-------------------------+
| 1610 |
+-------------------------+
1 row in set (0.00 sec)
MYSQL數(shù)據(jù)庫(kù)可以使用GROUP BY子句設(shè)置的各種記錄的總和.下面的例子將總結(jié)所有相關(guān)的記錄一個(gè)人,打印紙的每一個(gè)人總數(shù).
MYSQL數(shù)據(jù)庫(kù)
mysql> SELECT name, SUM(daily_typing_pages)
-> FROM employee_tbl GROUP BY name;
+------+-------------------------+
| name | SUM(daily_typing_pages) |
+------+-------------------------+
| Jack | 270 |
| Jill | 220 |
| John | 250 |
| Ram | 220 |
| Zara | 650 |
+------+-------------------------+
5 rows in set (0.17 sec)
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