Question

我有两个已连接的表格，“报告”和“访问次数”以及类似的查询：

SELECT reports.rep_dated,
(SELECT COUNT(*) FROM visits
WHERE visits.vis_report = reports.rep_id) AS vis_count
FROM reports
HAVING vis_count > 0
ORDER BY rep_dated

返回以下数据：

+------------+-----------+
| rep_dated  | vis_count |
+------------+-----------+
| 2013-11-03 | 3         |
| 2013-11-07 | 4         |
| 2013-11-28 | 2         |
| 2013-11-28 | 3         |
+------------+-----------+

到目前为止一直这么好（你看到rep_dated可以重复，因为它不是主键：那是因为第一个“2013-11-28”指的是完成AM的访问，第二个指的是完成的访问PM）< / p>

现在我想在同一天的时间内完成访问（也就是访问AM + PM的SUM次数），然后返回：

+------------+-----------+
| rep_dated  | vis_count |
+------------+-----------+
| 2013-11-03 | 3         |
| 2013-11-07 | 4         |
| 2013-11-28 | 5         |
+------------+-----------+

而且，正如你已经想象的那样，这就是我被卡住的地方......

GROUP BY reports.rep_dated不起作用......我怎么能得到那套呢？在此先感谢您的帮助！

Answer 1

试试这个：

SELECT reports.rep_dated, SUM(visits.vis_report) AS vis_count
FROM reports, visits
WHERE visits.vis_report = reports.rep_id
GROUP BY reports.rep_dated
HAVING vis_count > 0
ORDER BY rep_dated

Answer 2

在Mysql中使用Group By或ORDER时，您不需要提及表名。试试

GROUP BY rep_dated

Answer 3

试试这个：

SELECT reports.rep_dated,
       COUNT(*) AS vis_count
FROM VISITS
JOIN reports ON visits.vis_report = reports.rep_id
GROUP BY reports.rep_dated
ORDER BY reports.rep_dated

在此MySQL查询中对记录进行分组和汇总

3 个答案: