Basically, I have a table which looks like this:
Table: People
------------------------
ID | Employee
------------------------
1 | Saul
2 | Jess
3 | Kenny
And then I have another table that looks like this:
Table: Projects
------------------------
ID | Project | Employee
------------------------
1 | pro1 | 3
2 | pro2 | 1
3 | pro3 | 2
The problem is that I want to replace the numbers in the Employee column of the Projects table with the corresponding names of the employees in the People table.
Thanks in advance.
You don't need to replace the ID Number, you need to build a query to show the results you want.
An example query can be:
SELECT Projects.ID, Projects.Project, People.Employee
FROM Projects
INNER JOIN People on Projects.Employee = People.ID
This will result in:
+----+---------+----------+
| ID | Project | Employee |
+----+---------+----------+
| 1 | pro1 | Kenny |
| 2 | pro2 | Saul |
| 3 | pro3 | Jess |
+----+---------+----------+
Related
I have 2 tables
Table1: customers:
-------------
| id | name |
-------------
| 1 | Mark |
-------------
| 2 | Tom |
-------------
| 3 | John |
Table2: sales:
-----------------------------------
|sid | customerid | price | state |
-----------------------------------
| 10 | 1 | 12000 | 0 |
-----------------------------------
| 11 | 2 | 13500 | 1 |
-----------------------------------
| 12 | 2 | 23000 | 1 |
-----------------------------------
| 13 | 3 | 26000 | 0 |
-----------------------------------
| 14 | 1 | 66000 | 1 |
-----------------------------------
the state column is 0=no dep and 1=dept
I want to list the customers that have DEPT by checking them in the sales table. Now i'm looping the customers and checking them one by one. and it works! but when the number of rows in the customer table grows the page slows down. i want to make this by an SQL query. can anyone help me please ?
the result will be like this:
Mark 66000
Tom 36500
By the Following query, you will get the same output as you want. The joining of tables will be executed on the filtered data using where condition
$this->db->select('customers.name,sum(sales.price)')
->from('customers')
->join('sales','sales.customerid = customers.id','left')
->where('sales.state !=0')
->group_by('customers.name');
->get()->result_array();
You can simply group by customer id in sales table. Code will be like this
return $this->db->select('MAX(customers.name) AS name, SUM(sales.price) as price')->join('sales', 'sales.customerid = customers.id')->where('sales.state', 1)->group_by('customers.id')->get('customers')->result();
I have 3 tables
QUESTION table with below 2 properties
1. ID (serial)
2. Question (varchar)
ANSWER table with below 4 properties
1. ID (serial)
2. QuestionID (foreign key to table QUESTION)
3. StudentID (foreign key to table STUDENT)
4. ANSWER (varchar)
5. SubmitDateTime (datetime)
STUDENT table with below properties
1. ID (serial)
2. Name (varchar)
I just want to show records with each student (one record for each student) with every answer. If any question's answer is not given by the student it will show blank.
For example:
QUESTION TABLE
| ID | QUESTION |
|----- | --------- |
| 1 | A FOR? |
| 2 | B FOR? |
| 3 | C FOR? |
ANSWER TABLE
| ID | QuestionID | StudentID | ANSWER | SubmitDateTime |
|----- | ----------- |------------|--------|----------------|
| 1 | 1 | 1 |Apple | something date |
| 2 | 1 | 2 |Ant | something date |
| 3 | 2 | 1 |Book | something date |
| 4 | 3 | 2 |Cat | something date |
STUDENT TABLE
| ID | NAME |
|----- | --------- |
| 1 | Jhon |
| 2 | Lily |
Expected Records
Result table
| ID | NAME | Answers |
|----- | --------- | ---------------------|
| 1 | Jhon | Apple,Book,<blank> |
| 2 | Lily | Ant,<blank>,Cat |
"blank" means no record will be shown instead of a blank space or a hyphane.
My implementation:
SELECT s.ID,s.Name,
GROUP_CONCAT(a.answer SEPARATOR ',') AS answers
FROM student AS s
LEFT JOIN answer AS a ON a.studentID=s.ID
WHERE a.submitdate BETWEEN '<somedate>' AND '<somedate>'
GROUP BY s.ID ORDER BY a.ID ASC
It does not give me a blank answer. How to get these?
Try this:
SELECT sid, sname, GROUP_CONCAT(IFNULL(a.answer,'-') ORDER BY qid)
FROM
(SELECT q.id AS qid, s.id AS sid, s.Name AS sname
FROM question q CROSS JOIN student s) qs
LEFT JOIN answer a ON qs.qid=a.QuestionID AND qs.sid=a.StudentID
GROUP BY sid, sname;
The base query is a CROSS JOIN between question and student tables that will be a subquery and give a result like this:
+-----+-----+-------+
| qid | sid | sname |
+-----+-----+-------+
| 1 | 2 | Lily |
| 1 | 1 | Jhon |
| 2 | 2 | Lily |
| 2 | 1 | Jhon |
| 3 | 2 | Lily |
| 3 | 1 | Jhon |
+-----+-----+-------+
As you can see, each of the student will be paired with all of the existing question regardless of their answer records in answer table. This will be the reference for the LEFT JOIN with answer table.
Demo fiddle
I have 2 tables like this:
Table person
id | name
---------
1 | john
2 | mike
3 | carl
4 | keny
5 | anna
Table vehicle
owner | vechicle
----------------
1 | RTA457
3 | GSW684
3 | GKI321
3 | SNE798
5 | YTT662
So, I want to make a query joining both tables, something like this:
SELECT * FROM person LEFT JOIN vehicle ON person.id=vehicle.owner
Getting these results
id | name | owner | vechicle
----------------------------
1 | john | 1 | RTA457
2 | mike | NULL | NULL
3 | carl | 3 | GSW684
3 | carl | 3 | GKI321
3 | carl | 3 | SNE798
4 | keny | NULL | NULL
5 | anna | 5 | YTT662
Finally, I want to limit it to 3 persons, showing all their vehicles, like this:
id | name | owner | vechicle
----------------------------
1 | john | 1 | RTA457
2 | mike | NULL | NULL
3 | carl | 3 | GSW684
3 | carl | 3 | GKI321
3 | carl | 3 | SNE798
There is any way to do it?
May help with a subquery
SELECT
*
FROM
(SELECT * FROM person LIMIT 3) t
LEFT JOIN vehicle ON t.id = vehicle.owner
Didn't try it, but something like this:
SELECT * FROM person
LEFT JOIN vehicle ON person.id = vehicle.owner
WHERE person.id IN (SELECT ID FROM PERSON LIMIT 3);
You could simply have your query as such:
SELECT * FROM person LEFT JOIN vehicle ON person.id=vehicle.owner LIMIT 10;
This SO could be handy as well. Hope this helps!
I have one database here
1st table is conversation table
___________________________
| id | conversation Name |
__________________________
| 1 | member and officer |
___________________________
| 2 | member and guests |
___________________________
2nd table is user table
_________________
| id | name |
_________________
| 1 |member |
_________________
| 2 |officer |
_________________
| 3 |guest |
_________________
3rd table is conversation_user_involved table
_________________________________
| id_conversation | id_user |
_________________________________
| 1 | 1 |
_________________________________
| 1 | 2 |
_________________________________
| 2 | 1 |
_________________________________
| 2 | 3 |
_________________________________
The question is how do I select conversation based on user.
Let say the input user parameter is 1 and 2 so that mean user 1 is member and 2 is officer.
How can I select the conversation member and officer?
I have tried "IN" query but it didnt work.
untested:
select id_conversation, conversation_Name
from conversation_user_involved
inner join conversation on (id_conversation = conversation.id)
where id_user in (1, 2)
group by id_conversation
having count(id_conversation) = 2
I'm new to relational sql. I'm trying to figure out a query to return the names of customers who have more than one type of account.
customers:
+------------+--------------+
| cid | Name |
+------------+--------------+
| 1 | Bob |
| 2 | John |
| 3 | Jane |
+------------+--------------+
accounts:
+------------+--------------+
| aid | type |
+------------+--------------+
| 1 | Checking |
| 2 | Saving |
| 3 | CD |
+------------+--------------+
transactions:
+------------+--------------+--------------+
| tid | cid | aid |
+------------+--------------+--------------+
| 1 | 1 | 1 |
| 2 | 2 | 1 |
| 3 | 1 | 2 |
| 4 | 2 | 3 |
| 5 | 3 | 1 |
+------------+--------------+--------------+
With these tables, the query should return Bob and John. I'm having some trouble with how to write such a query. More specifically, how do I keep count of how many accounts a customer has and how do I compare if the accounts are different without adding a new column to the table?
Okay, this seems to work in SQL Fiddle with my test data structure. Try it out with your real data structure and see if it gives you what you're looking for.
SELECT name FROM customers c WHERE EXISTS(
SELECT DISTINCT aid FROM transactions
WHERE cid = c.cid
HAVING COUNT(DISTINCT aid)>1
)