mysql tables are as follows
+------------+----------------+----------------+
| booking_id | boarding_point | dropping_point |
+------------+----------------+----------------+
| 1 | 2 | 4 |
| 2 | 1 | 2 |
+------------+----------------+----------------+
+-------------+---------------+
| location_id | location_name |
+-------------+---------------+
| 1 | chennai |
| 2 | coimbatore |
| 3 | tiruppur |
| 4 | erode |
| 5 | salem |
+-------------+---------------+
boarding_point and dropping_point are foreign keys for location_id.
Now I want the select query to display like
+------------+----------------+----------------+
| booking_id | boarding_point | dropping_point |
+------------+----------------+----------------+
| 1 | coimbatore | erode |
| 2 | chennai | coimbatore |
+------------+----------------+----------------+
can anyone please suggest me the query to display like above.
Join the booking table twice to the location table:
SELECT
b.booking_id,
t1.location_name,
t2.location_name
FROM booking b
INNER JOIN location t1
ON b.boarding_point = t1.location_id
INNER JOIN location t2
ON b.dropping_point = t2.location_id;
Demo
Related
There are two tables,
Table A has a three-level structure that looks like
| id | name | level | up_level_id |
| :------- | :-------: | :------: | ----------:|
| 1 | lv1_name1 | 1 | null |
| 2 | lv1_name2 | 1 | null |
| 3 | lv2_name1 | 2 | 1 |
| 4 | lv2_name2 | 2 | 2 |
| 5 | lv3_name1 | 3 | 3 |
| 6 | lv3_name2 | 3 | 3 |
| 7 | lv3_name3 | 3 | 4 |
| 8 | lv3_name4 | 3 | 4 |
Table B looks like
| amount | org_id |
| -------- | -------- |
| 12,000 | 5 |
| 15,000 | 6 |
| 20,000 | 7 |
| 18,000 | 8 |
Table A and Table B can be joined on A.id=B.org_id, but they are all at the level-3 of Table A（Only level-3 has their amount）
I want to query the top-level name,level-1 name, and the summary amount that looks like
| sum_amount | top_lvl_name |
| -------- | -------- |
| 27,000 | lv1_name1 |
| 38,000 | lv1_name2 |
For Testing, I have already accomplished the query of the level-1 name from the level-3 id in TableA
The SQL is as follows
SELECT name
FROM TableA
WHERE id IN (
SELECT up_level_id
FROM Table A
WHERE id IN (
SELECT up_level_id
FROM Table A
WHERE id=5) --query the id:5's top-level name
);
But when I join these two tables as follows, it goes wrong
SELECT sum(amount) AS sum_amount, name AS top_lvl_name
FROM TableA, TableB
WHERE id = org_id
AND id IN (
SELECT up_level_id
FROM TableA
WHERE id IN (
SELECT up_level_id
FROM TableA
WHERE TableA.id IN(
SELECT org_id
FROM TABLEB
)
)
);
I get nothing as above
What can I do to make this query to be correct?
Thanks for everyone's answer and comment.
Finally, I find it very difficult to query the result as I wish. So, I've come up with a shortcut——create a new table that a three-level structure recorded horizontally, which looks like
| lv1_id | lv2_name | lv2_id | lv2_name | lv3_id | lv3_name |
| :------- | :-------: | :------: | :----------:| :------: | :----------:|
| 1 | lv1_name1 | 3 | lv2_name1 | 5 | lv3_name1 |
| 1 | lv1_name1 | 3 | lv2_name1 | 6 | lv3_name2 |
| 2 | lv1_name2 | 4 | lv2_name1 | 7 | lv3_name3 |
| 2 | lv1_name2 | 4 | lv2_name1 | 8 | lv3_name4 |
As above,I can easily connect two tables
I have a MySQL database including following tables that used to maintain transactions of some documents.
tbl_documents Table
+----+---------+------+---------+
| id | file_no | name | subject |
+----+---------+------+---------+
| 1 | A/10 | F1 | a |
| 2 | A/11 | F2 | b |
| 3 | A/12 | F3 | c |
| 4 | A/13 | F4 | d |
+----+---------+------+---------+
tbl_requests
+----+-------------+----------------+---------------+
| id | document_id | requested_date | approved_date |
+----+-------------+----------------+---------------+
| 1 | 1 | 2019-12-01 | 2019-12-02 |
| 2 | 2 | 2019-12-08 | 2019-12-08 |
+----+-------------+----------------+---------------+
tbl_issues
+----+-------------+------------+
| id | document_id | issue_date |
+----+-------------+------------+
| 1 | 1 | 2019-12-05 |
| 2 | 2 | 2019-12-10 |
+----+-------------+------------+
I want to get the following / Desired output by joining above three tables.
Desired Output
+---------+------+---------+----------------+---------------+------------+
| file_no | name | subject | requested_date | approved_date | issue_date |
+---------+------+---------+----------------+---------------+------------+
| A/10 | F1 | a | 2019-12-01 | 2019-12-02 | 2019-12-05 |
| A/11 | F2 | b | 2019-12-08 | 2019-12-08 | 2019-12-10 |
+---------+------+---------+----------------+---------------+------------+
To do that, I used the following query
select tbl_documents.file_no, tbl_documents.name, tbl_documents.subject, requested_date, approved_date, tbl_issues.issue_date
from tbl_documents
right join tbl_requests on tbl_requests.document_id=tbl_documents.id
right join tbl_issues on tbl_issues.document_id=tbl_documents.id
But didn't get the expected output. Can anyone help ?
Just use inner joins, as in:
select
d.file_no,
d.name,
d.subject,
r.requested_date,
r.approved_date,
i.issue_date
from tbl_documents d
join tbl_requests r on r.document_id = d.id
join tbl_issues i on i.document_id = d.id
student table
|----------------------|
| student_id | name |
|------------|---------|
| 1 | Richard |
| 2 | Emily |
| 3 | Hans |
|------------|---------|
lecturer table
|--------------------|
| lecturer_id | name |
|-------------|------|
| 1 | John |
| 2 | Mike |
|-------------|------|
classes table
|-----------------------------------------------|
| class_id | lecturer_id | material |
|----------|-------------|----------------------|
| 1 | 1 | Basic of algorithm |
| 2 | 1 | Basic of programming |
| 3 | 2 | Database Essentials |
| 4 | 2 | Basic of SQL |
|----------|-------------|----------------------|
attendance table
|-----------------------|
| class_id | student_id |
|----------|------------|
| 1 | 1 |
| 1 | 2 |
| 1 | 3 |
| 2 | 1 |
| 2 | 2 |
| 3 | 1 |
| 3 | 2 |
| 3 | 3 |
| 4 | 1 |
| 4 | 2 |
|----------|------------|
how to show classes records (from classes table) that not attended by Hans (student) in MySQL?
desired result :
|-----------------------------------------------|
| class_id | lecturer_id | material |
|----------|-------------|----------------------|
| 2 | 1 | Basic of programming |
| 4 | 2 | Basic of SQL |
|----------|-------------|----------------------|
One approach uses EXISTS:
SELECT c.class_id, c.lecturer_id, c.material
FROM classes c
WHERE NOT EXISTS (SELECT 1 FROM attendance a
INNER JOIN student s
ON a.student_id = s.student_id
WHERE a.class_id = c.class_id AND
s.name = 'Hans');
Using joins -
select c.class_id
from attendance a inner join student s on (a.student_id=s.student_id and s.student_id='Hans')
right outer join classes c on (a.class_id=c.class_id)
where a.class_id is null
There are my two tables:
Table name: FRIENDS
+-------+---------+---------+-------------------+
| id | firstName | lastName | city |
+-------+--------------+------------+-----------+
| 1 | dudi | edri | london |
| 2 | maor | azulay | madrid |
| 3 | batel | azulay | tel aviv |
| 4 | nir | cohen | barcelona |
| 5 | evia | perez | miami |
| 6 | neria | perez | new-york |
| 7 | nevo | kakoun | roma |
+-------+---------+---------+-------------------+
Table name: ORDERS
+-------+---------+---------+-----------------+
| id | firstName | amount | status |
+-------+--------------+----------+-----------+
| 1 | dudi | 5684 | shipped |
| 2 | maor | 4896 | shipped |
| 3 | batel | 2496 | delay |
+-------+--------------+----------+-----------+
my question is:
I want the friends that have no order.
The answer:
| 4 | nir | cohen | barcelona |
| 5 | evia | perez | miami |
| 6 | neria | perez | new-york |
| 7 | nevo | kakoun | roma |
+-------+---------+---------+-------------------+
how i wrote the query with inner join.
Thanks.
You shouldn't use firstName in ORDERS as Foreign Key. The foreign key should reference the primary key. Use ID from FRIENDS like:
Table name: ORDERS
+-------+---------+---------+-----------------+
| id | friendID | amount | status |
+-------+--------------+----------+-----------+
| 1 | 1 | 5684 | shipped |
| 2 | 2 | 4896 | shipped |
| 3 | 3 | 2496 | delay |
+-------+--------------+----------+-----------+
And query using LEFT OUTER JOIN:
SELECT f.*
FROM FRIENDS f
LEFT JOIN ORDERS o
ON f.ID = o.friendID
WHERE o.ID IS NULL;
LiveDemo
Another possibility is to use correlated subquery:
SELECT f.*
FROM FRIENDS f
WHERE NOT EXISTS (SELECT 1
FROM orders o
WHERE o.friendID = f.ID);
LiveDemo2
Tables:
CREATE TABLE friends(
id INTEGER NOT NULL PRIMARY KEY -- you can add AUTO_INCREMENT if needed
...
);
CREATE TABLE orders(
id INTEGER NOT NULL PRIMARY KEY
,friendID INTEGER NOT NULL
,FOREIGN KEY (friendID) REFERENCES friends(id)
...
);
I have searched and gone through the available topics similar to mine. But, failed to find that satisfies my requirements. Hence, posting it here.
I have four tables as follows:
"Organization" table:
--------------------------------
| org_id | org_name |
| 1 | A |
| 2 | B |
| 3 | C |
"Members" table:
----------------------------------------------
| mem_id | mem_name | org_id |
| 1 | mem1 | 1 |
| 2 | mem2 | 1 |
| 3 | mem3 | 2 |
| 4 | mem4 | 3 |
"Resource" table:
--------------------------------
| res_id | res_name |
| 1 | resource1 |
| 2 | resource2 |
| 3 | resource3 |
| 4 | resource4 |
"member-resource" table:
--------------------------------------------
| sl_no | mem_id | res_id |
| 1 | 1 | 1 |
| 2 | 1 | 2 |
| 3 | 2 | 1 |
| 4 | 4 | 3 |
| 5 | 3 | 4 |
| 6 | 2 | 3 |
| 7 | 4 | 3 |
I want to find out the total number of distinct resources according to organizations. Expected output is as follows:
| org_name | Total Resources |
| A | 3 |
| B | 1 |
| C | 1 |
I also want to find out the total number of shared resources according to organizations. Expected output is as follows:
| org_name | Shared Resources |
| A | 1 |
| B | 0 |
| C | 1 |
Any help in this regard will highly be appreciated.
Regards.
It is much simpler than you think, particularly because you don't even need the resource table:
SELECT o.org_name, COUNT(DISTINCT mr.res_id) TotalResources
FROM member_resource mr
JOIN members m ON mr.mem_id = m.mem_id
JOIN organization o ON m.org_id = o.org_id
GROUP BY o.org_id
Output:
| ORG_NAME | TOTALRESOURCES |
|----------|----------------|
| A | 3 |
| B | 1 |
| C | 1 |
Fiddle here.
Try this query below.
SELECT org_name, COUNT(DISTINCT res_id)
FROM organization, members, member-resource
WHERE members.mem_id = member-resource.mem_id
AND organization.org_id = members.org_id
GROUP BY org_id, org_name