Question

我有下表

id    group_id   user_id
1     2          11
2     2          12
3     2          13
4     3          11
5     3          12
6     4          11

现在我想要公共组ID意味着

I pass user_id (11,12) then result will be group_id (2 and 3)
I pass user_id (11) then result will be group_id (2,3 and 4)
I pass user_id (11,12,13) then result will be group_id (2)
I pass user_id (13,15) then result will be zero group_id (NULL)

我正在使用CodeIgniter但您可以在核心SQL中建议我。如果您的答案是CI模型（查询）标准，那将是件好事。

Answer 1

您可以使用distinct和where_in来获得您的愿望结果。 array包含user_id

的位置

$this->db->distinct();
$this->db->select('group_id');
$this->db->from('your_table');
$this->db->where_in('user_id',array('11','12');//you can pass here 11,12,13 or 11 or 11,12

For And Condition

$array = array('user_id' => 11, 'user_id' => 12);

    $this->db->distinct();
    $this->db->select('group_id');
    $this->db->from('your_table');
    $this->db->where($array);

Answer 2

SELECT *, group_concat(DISTINCT(group_id)) FROM test_temp WHERE user_id IN(11,12)

Answer 3

一种方法是使用SQL的NATURAL JOIN。

对于user_id = 11

SELECT group_id FROM table_name WHERE user_id = 11;

对于user_id = 11,12

SELECT group_id FROM 
    (SELECT group_id FROM table_name WHERE user_id = 11) t1 
        NATURAL JOIN 
    (SELECT group_id FROM table_name WHERE user_id = 12) t2;

对于user_id = 11,12,13

SELECT group_id FROM 
    (SELECT group_id FROM table_name WHERE user_id = 11) t1 
        NATURAL JOIN 
    (SELECT group_id FROM table_name WHERE user_id = 12) t2 
        NATURAL JOIN 
    (SELECT group_id FROM table_name WHERE user_id = 13) t3;

Codeigniter：获取相同值之间的公共列值

3 个答案: