如何选择表组中的所有行和sql中每个组的联系计数 [英] how do select all rows from table groups and count of contacts for each groups in sql
问题描述
大家好
i有2个表:1-组2-联系人
组表fileds是:
1-group_id
2-group_name
联系人表格文件是:
1-contact_group_id
2-contact_id
3-contact_name
现在,我想要选择所有群组的联系人数
例如:
groupname contacts数量
frined 12
学校8
敌人0
家庭25 < br $> b $ b
i希望所有群体显示(包括没有任何联系人的群组)
非常感谢
SELECT group_name AS groupname,COUNT(contact_group_id) AS [联系人计数] FROM groups LEFT JOIN contacts ON
group_id = contact_group_id GROUP BY group_name,contact_group_id
hi all
i have 2 table : 1- groups 2- contacts
groups table fileds are :
1-group_id
2-group_name
contacts table fileds are :
1-contact_group_id
2-contact_id
3-contact_name
now , i want select all groups with count of group's contacts
example :
groupname contacts count
frined 12
school 8
Enemy 0
family 25
i want all groups dispaly(include groups that have not any contacts)
thanks a lot
SELECT group_name AS groupname, COUNT(contact_group_id) AS [contacts count] FROM groups LEFT JOIN contacts ON group_id = contact_group_id GROUP BY group_name, contact_group_id
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