本文介绍了SQL;只计算每列中指定的值的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
在SQL中,我有一个名为answer的列,值可以是1或2.我需要生成一个SQL查询,计算每个月的1和2的数量。我有以下查询,但它不工作:
In SQL I have a column called "answer", and the value can either be 1 or 2. I need to generate an SQL query which counts the number of 1's and 2's for each month. I have the following query, but it does not work:
SELECT MONTH(`date`), YEAR(`date`),COUNT(`answer`=1) as yes, COUNT(`answer`=2) as nope,` COUNT(*) as total FROM results GROUP BY YEAR(`date`), MONTH(`date`)推荐答案
尝试SUM-CASE技巧:
Try the SUM-CASE trick:
SELECT MONTH(`date`), YEAR(`date`), SUM(case when `answer` = 1 then 1 else 0 end) as yes, SUM(case when `answer` = 2 then 1 else 0 end) as nope, COUNT(*) as total FROM results GROUP BY YEAR(`date`), MONTH(`date`)更多推荐
SQL;只计算每列中指定的值
发布评论