+--------------+
| month | year |
+-------+------+
| jan | 2015 |
| jan | 2015 |
| jan | 2015 |
| feb | 2015 |
| feb | 2015 |
| feb | 2015 |
| feb | 2015 |
| feb | 2015 |
| mar | 2015 |
| mar | 2015 |
| mar | 2015 |
| mar | 2015 |
| mar | 2015 |
| mar | 2015 |
| mar | 2015 |
| mar | 2016 |
| mar | 2016 |
| mar | 2016 |
| mar | 2016 |
| mar | 2016 |
| mar | 2016 |
| mar | 2016 |
| mar | 2016 |
| feb | 2016 |
| feb | 2016 |
| jan | 2016 |
| jan | 2016 |
| jan | 2016 |
| jan | 2016 |
+--------------+
这是桌子。
我需要每个月的平均率（即月/年）
您应该计算month列而不是*。
这是查询：
SELECT (COUNT(my.`month`)/(SELECT COUNT(*) FROM crate inmn WHERE inmn.`year` = my.`year`)) AS num, my.`month`, my.`year` FROM crate my GROUP BY my.`month`,my.`year;
以上查询将month特别给出一个平均值year。
本文收集自互联网，转载请注明来源。
如有侵权，请联系[email protected] 删除。
我来说两句