我有三个表，它们是以下
用户表
+---------+-----------+--------+
| user_id | user_name | branch |
+---------+-----------+--------+
| 1 | John | 1 |
| 2 | Jim | 2 |
| 3 | Jern | 3 |
| 4 | Jack | 1 |
| 5 | Jery | 2 |
| 6 | Tom | 3 |
| 7 | Sona | 1 |
| 8 | Tina | 3 |
+---------+-----------+--------+
分支表
+-----------+----------------+
| branch_id | branch_name |
+-----------+----------------+
| 1 | IT |
| 2 | SALES |
| 3 | Administration |
+-----------+----------------+
查询表
+------------+---------------+---------+
| enquiry_id | enquiry_name | user_id |
+------------+---------------+---------+
| 1 | enqury_test1 | 1 |
| 2 | enqury_test2 | 2 |
| 3 | enqury_test3 | 1 |
| 4 | enqury_test4 | 3 |
| 5 | enqury_test5 | 2 |
| 6 | enqury_test6 | 5 |
| 7 | enqury_test7 | 1 |
| 8 | enqury_test8 | 2 |
| 9 | enqury_test9 | 4 |
| 10 | enqury_test10 | 6 |
| 11 | enqury_test11 | 2 |
| 12 | enqury_test12 | 7 |
+------------+---------------+---------+
从上表可以清楚地看出，每个分支都包含许多用户。这些用户发布多个查询。我需要获得每个分支机构的查询总数作为
branch id => number of enquiries
我试过各种各样的问题。但我没能得到结果。有人能帮忙吗？我使用的是MySQL，需要单个查询来执行此操作。
提前感谢
您需要count和group by
select
b.branch_id,
count(e.user_id) as `total_enq`
from Branch b
left join User u on u.branch = b.branch_id
left join Enquiry e on e.user_id = u.user_id
group by b.branch_id
要获得所需结果，必须执行的查询如下：-
$query = "SELECT u.branch, COUNT(u.user_id) AS `total_enquires`
FROM enquiry e INNER JOIN user u ON e.user_id = u.user_id
GROUP BY u.branch"
这将对您有所帮助，我认为您不需要加入分支表，因为用户表格已经包含branch_id。
这是查询
SELECT `branch`,`branch_name`,count(`user`.`user_id`),count(`enquiry_id`) FROM `user` inner join `branch` on `user`.`branch`=`branch`.`branch_id` inner join `enquiry` on `user`.`user_id`=`enquiry`.`user_id` group by `branch`
在这里试试http://sqlfiddle.com/#！9/cf3eb/1
SELECT
bt.branch_id
,COUNT(enquiry_id) AS total_enquiry
FROM
enquiry_table et
INNER JOIN user_table ut on ut.user_id = et.user_id
INNER JOIN branch_table bt ON bt.branch_id = ut.branch
WHERE
1=1
GROUP BY
bt.branch_id
你可以试试这个