我在 php 文件中的 MYSQL 代码查询有什么问题？

Question

I have two tables in mysql database

one table named is place:

place_id	place	active	shortform	country	type
1	Uttar Pradesh	1	UP	India	State
2	Delhi	1	DELHI	India	Union territory
3	Punjab	1	PUN	India	State
4	Karnataka	1	KAR	India	State
5	Kerala	1	KER	India	State
6	Lucknow	1	LKO	India	Capital
7	Chandigarh	1	CHA	India	Capital
8	Bengaluru	1	BEN	India	Capital
9	Thiruvanthapuram	1	THI	India	Capital
10	Saharanpur	1	SAH	India	District
11	Meerut	1	MEE	India	District
12	Gorakhpur	1	GOR	India	District

and other named as place_capital

id_place_place	place_parent	place_child
1	1	6
2	3	7
3	4	8
4	5	9
5	1	10
6	1	11
7	1	12

I run this query

select *, group_concat(place_capital.place_child) AS Group from place
left join place_capital on place.place_id = place_place.place_parent
where place.place_id = place_place.place_parent and active = :active AND type = :type
group by place ORDER BY place

and it give the following result

place_id	place	active	shortform	country	type	id_place_place	place_parent	place_child	Group
1	Uttar Pradesh	1	UP	India	State	1	1	6	6,10,11,12
3	Punjab	1	PUN	India	State	2	3	7	NULL
4	Karnataka	1	KAR	India	State	3	4	8	NULL
5	Kerala	1	KER	India	State	4	5	9	NULL

What query I used in php file to give the following result that include Delhi also. The place table have some relationship with place_place table . with my above sql query that not give the Delhi in the result. So, what is the thing I missed in the php file to get the below result.

place_id	place	active	shortform	country	type	id_place_place	place_parent	place_child	Group
1	Uttar Pradesh	1	UP	India	State	1	1	6	6,10,11,12
2	Delhi	1	DELHI	India	Union Territory	NULL	NULL	NULL	NULL
3	Punjab	1	PUN	India	State	2	3	7	NULL
4	Karnataka	1	KAR	India	State	3	4	8	NULL
5	Kerala	1	KER	India	State	4	5	9	NULL

and here is the code in the php file:-

public function __construct(Querier $db, $type = "", $active = 1) {
    $this->db = $db;
    $this->type = $type;
    $this->active = $active;

    $connection = $this->db->getConnection();

    if ($this->type != "") {
        $statement = $connection->prepare("select *, group_concat(place_capital.place_child) AS Group from place
                                        left join place_capital on place.place_id = place_place.place_parent
                                        where place.place_id = place_place.place_parent and active = :active AND type = :type
                                        group by place ORDER BY place ");
        $statement->bindParam(":type", $this->type);
    } else {
        $statement = $connection->prepare("SELECT * FROM place WHERE active = :active ORDER BY place ");
    }

    $statement->bindParam(":active", $this->active);
    $statement->execute();
    $this->_guide_list = $statement->fetchAll();

}

Answer 1

As I can see here you only filter based on state and Delhi is Union Territory so to include that in a list you need to use In operator to filter type. you can also skip a join condition from where clause.

SELECT *,
   Group_concat(place_capital.place_child) AS Group
FROM   place
   left join place_capital
          ON place.place_id = place_capital.place_parent
WHERE active = 1
   AND TYPE IN ('State', 'Union Territory')
GROUP  BY place.place_id
ORDER  BY place.place_id