Warning: file_get_contents(/data/phpspider/zhask/data//catemap/8/mysql/66.json): failed to open stream: No such file or directory in /data/phpspider/zhask/libs/function.php on line 167

Warning: Invalid argument supplied for foreach() in /data/phpspider/zhask/libs/tag.function.php on line 1116

Notice: Undefined index: in /data/phpspider/zhask/libs/function.php on line 180

Warning: array_chunk() expects parameter 1 to be array, null given in /data/phpspider/zhask/libs/function.php on line 181
Mysql 是否可以编写单个查询?_Mysql - Fatal编程技术网

Mysql 是否可以编写单个查询?

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 | +----+-----------+----------+------------+-

第一表:问题

+----+-----------+----------+------------+-------------+----------+-----------+-----------+-------+
| 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

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?