Question

使用Mysql ---我必须得到每月反馈记录等于零的提供商数量，我不知道如何构建这个问题来搜索谷歌我有7个表主题，与会者，反馈，日期，学生，分支，提供商，以下给出了这些表的模型

    **feedback**:
            id -  12
            attendee_id - 32
            comment - good learning from him
            created - 2012-03-08 01:12:46

            **attendee**:
            id - 32
            student_id - 345
            topic_id - 128
            created - 2014-01-07 07:50:38
            class - topic


     **student**:
            id - 345
            branch_id - 56
            created - 2012-07-11 09:47:35

            **provider**:
            id - 67
            name - narik
            created - 2010-01-19 01:30:58

            **branch**:
            id - 56
            name - vize creators
            provider_id - 67
            created - 2010-01-19 01:30:58


             **topic**:
                id - 128
                name - photography
                group - photo
                created - 2010-01-19 01:30:58

    **desc date:**
    +-------+------------------+------+-----+---------+----------------+
    | Field | Type             | Null | Key | Default | Extra          |
    +-------+------------------+------+-----+---------+----------------+
    | date  | date             | NO   | PRI | NULL    |                |
    | week  | varchar(100)     | NO   |     | NULL    |                |
    | month | varchar(100)     | NO   |     | NULL    |                |
    | day   | varchar(100)     | NO   |     | NULL    |                |
    | year  | varchar(4)       | NO   |     | NULL    |                |
    | id    | int(10) unsigned | NO   | MUL | NULL    | auto_increment |
    +-------+------------------+------+-----+---------+----------------+

这是我试过的

select count(distinct p.id),d.month,t.group
from attendee a, feedback cf, topic t ,date d,student es,branch b,provider p
where date(cf.created)=d.date and p.id=b.provider_id and year(cf.created)=2014 and a.class='TopicAttendee' and a.topic_id=t.id and t.group in ('Education','Fit','Graphics','Services') and es.branch_id=b.id and a.student_id=es.id and a.id=cf.attendee_id and cf.status='ACTIVE' and comment is not null and comment != ''
 group by d.month,es.branch_id having count(distinct cf.id)=0;

它给我空集（可能是因为查询错误）但我有我的数据库中没有反馈记录的提供者

获得具有另一个表字段的计数的一个表字段的计数的方法等于零

0 个答案: