Mysql 是否可以编写单个查询?
第一表:问题Mysql 是否可以编写单个查询?,mysql,Mysql,第一表:问题 +----+-----------+----------+------------+-------------+----------+-----------+-----------+-------+ | id | createdBy | question | attachment | contributor | doctorId | ipAddress | userAgent | views | +----+-----------+----------+------------+-
+----+-----------+----------+------------+-------------+----------+-----------+-----------+-------+
| id | createdBy | question | attachment | contributor | doctorId | ipAddress | userAgent | views |
+----+-----------+----------+------------+-------------+----------+-----------+-----------+-------+
| 1 | 1 | hiii | NULL | NULL | 3 | NULL | NULL | NULL |
+----+-----------+----------+------------+-------------+----------+-----------+-----------+-------+
第二个表:视图
+----+-----------+--------+-------+------------+
| id | ipAddress | userId | count | questionId |
+----+-----------+--------+-------+------------+
| 1 | NULL | 1 | NULL | 1 |
+----+-----------+--------+-------+------------+
我想要数据问题表id,createdBy,question,count(有多少用户从视图表中查看问题,其中question=1);
如何编写单个查询 一个简单的计数(不同的…)应该可以:-
SELECT COUNT(DISTINCT userId)
FROM view
WHERE question = 1
要获取问题的其他详细信息,请执行join并添加GROUPBY子句
SELECT question.id,
question.createdBy,
question.question,
COUNT(DISTINCT userId)
FROM view
INNER JOIN question
WHERE view.question = 1
GROUP BY id,
createdBy,
question
如果表名为question,并且您的question也是一个包含问题编号(id)的字段,而views字段包含问题的视图数量,那么您可以获得如下视图
从问题中选择视图,其中问题=1代码>这是我今天看到的最不清楚的问题。它就像一个国际边界或原始领域。你的名字在哪里p改进格式,只是问你想知道什么?