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我有一个表结构和样本数据是这样的:如何选择过去六个月的销售价值?
+----+-----------+------+-------+---------+
| id | item_code | year | month | sales |
+----+-----------+------+-------+---------+
| 1 | 12341 | 2011 | 10 | 1000000 |
+----+-----------+------+-------+---------+
| 2 | 12342 | 2011 | 11 | 2000000 |
+----+-----------+------+-------+---------+
| 3 | 12343 | 2011 | 12 | 3000000 |
+----+-----------+------+-------+---------+
| 4 | 12344 | 2012 | 01 | 4000000 |
+----+-----------+------+-------+---------+
| 5 | 12345 | 2012 | 02 | 5000000 |
+----+-----------+------+-------+---------+
| 6 | 12346 | 2012 | 03 | 6000000 |
+----+-----------+------+-------+---------+
| 7 | 12347 | 2012 | 04 | 6000000 |
+----+-----------+------+-------+---------+
现在的问题是,例如当前月份是2012年(04 - 2012)八月,我们该如何选择过去的半年数据,是:
+----+-----------+------+-------+---------+
| id | item_code | year | month | sales |
+----+-----------+------+-------+---------+
| 1 | 12341 | 2011 | 10 | 1000000 |
+----+-----------+------+-------+---------+
| 2 | 12342 | 2011 | 11 | 2000000 |
+----+-----------+------+-------+---------+
| 3 | 12343 | 2011 | 12 | 3000000 |
+----+-----------+------+-------+---------+
| 4 | 12344 | 2012 | 01 | 4000000 |
+----+-----------+------+-------+---------+
| 5 | 12345 | 2012 | 02 | 5000000 |
+----+-----------+------+-------+---------+
| 6 | 12346 | 2012 | 03 | 6000000 |
+----+-----------+------+-------+---------+
...并获得平均销售价值?有任何想法吗? TIA!
+1我首先想到的:) – Havelock 2012-08-13 08:27:56
然后得到平均,一个只需要'SELECT AVG(销售)FROM ...' – eggyal 2012-08-13 08:38:50
感谢您的想法,但该条款似乎没有哪里工作,它说:#1064 - 你的SQL语法错误;检查与您的MySQL服务器版本相对应的手册,以在'6 MONTH附近使用正确的语法。 – Mico 2012-08-13 11:18:52