I have a problem that I can't figure out, I'm not experienced enough (or it can't be done!) I've trawled Google for the answer with no luck.
I have a system where I need to assign an ID to each row, with the ID from another table. The catch is that the ID must be unique for each row created in this batch.
Basically I'm selling links on my Tumblr accounts, I need to assign a Tumblr account to each link that a customer purchases but I want to assign all possible Tumblr accounts so that duplicates are kept to the minimum possible.
The URLs - each link that a customer buys is stored in this table (urls_anchors):
+----------+--------------------+------------+-----------+------+
| clientID | URL | Anchor | tumblrID | paid |
+----------+--------------------+------------+-----------+------+
| 1234 | http://example.com | Click here | 67 | Yes |
| 1234 | http://example.com | Click here | 66 | Yes |
| 1234 | http://example.com | Click here | 65 | Yes |
| 1234 | http://example.com | Click here | 64 | Yes |
+----------+--------------------+------------+-----------+------+
All of the Tumblr accounts available for allocation are stored in this table (tumblrs):
+----------+-------------------+------------+
| tumblrID | tumblrURL | spacesLeft |
+----------+-------------------+------------+
| 64 | http://tumblr.com | 9 |
| 65 | http://tumblr.com | 9 |
| 66 | http://tumblr.com | 9 |
| 67 | http://tumblr.com | 9 |
+----------+-------------------+------------+
My best attempt at this has been the following query:
INSERT INTO `urls_anchors` (`clientID`, `URL`,`Anchor`, `tumblrID`, `paid`) VALUES ('$clientID','$url','$line', (SELECT #rank:=#rank+1 AS tumblrID FROM tumblrs WHERE #rank < 68 LIMIT 1), 'No')
Which works but keeps adding incrementally indefinitely, when there are only X number of Tumblrs to assign. I need the query to loop back around when it reaches the last row of Tumblrs and run through the list again.
Also i'm using this in a PHP script, I'm not sure if that's of any significance.
Any help would be MASSIVELY appreciated!
Thanks for looking :)
You can use a SELECT query as the source of data to insert.
INSERT INTO urls_anchors (`clientID`, `URL`,`Anchor`, `tumblrID`, `paid`)
SELECT '$clientID','$url','$line', tumblrID, 'No'
FROM tumblrs
LIMIT $number_of_rows
DEMO
This will assign $number_of_rows different tumblrID values to the rows.
If you need to assign more tumbler IDs than are available, you'll need to do this in a loop, subtracting the number of rows inserted from $number_of_rows each time. You can use mysqli_affected_rows() to find out how many rows were inserted each time.
Related
I have two tables where some same kind of information kept. One table has approved information and other one contains pending(waiting for approval) data. I fetch data from both table and display in a same view. So user will see data from both the tables. User can delete those records. But when deleting I've a trouble with finding out which table I should delete.
Assume, table1(Approved info), table2(Pending info)
table1
id | name | description | creator |
-----------------------------------
10 | test1 | N/A | 100 |
11 | test2 | N/A | 100 |
12 | test3 | N/A | 101 |
13 | test4 | N/A | 200 |
table2
id | name | description | creator |
-----------------------------------
10 | test1 | N/A | 105 |
11 | test2 | N/A | 103 |
12 | test3 | N/A | 106 |
13 | test4 | N/A | 202 |
table1 has a record with id of 10; and table2 has a record with id of 10 in that table. Id is the primary key of both tables. Both record will show to user. Let's say user wants to delete the record related to id 12 came from table2. So I want to delete that record from table2. But how can I figure out which table to delete that record. Because I can't use id to figure out the table. I have tried using some kind of data attribute attached with
data coming from table2 to differentiate them. But anyone can change them by inspecting it. So what is the proper way for solve this issue?
On any case, on any system, makes sense to have two to tables with same columns. That should be one of the firsts rules of database design. What's more, you discovered yourself how hard is to maintain a design like that. I see this on legacy systems developed with zero love to the code. In the future this will turn into a snowball. You should change it as soon as possible.
status column
The status of and entity or resource, is classic requirement, usually implemented with one little column which called : status, flag, mode, etc. In your case, it could have these values (#BhaumikPandhi comment):
pending/approved/rejected
id | name | description | creator | status |
--------------------------------------------
10 | test1 | N/A | 100 | pending|
If you are worried to the database optimization, you could use a tinyint with these equivalence in your documentation:
1 = pending
2 = approved
3 = rejected
status table
You could keep your first table called record
id | name | description | creator |
And create another one called record_status with 2 columns, in which record_id is a FK of record table
record_id | status |
Anyway, the status column is the most easy a classic approach to your requirement.
I have 2 tables. One with a list of clients and another with a list of data. I am trying to create a table in my view that lists the client name along with the sum of a column(job_total) in the data table. I am able to write a query that works fine in most situations. The problem is, if I have not yet created a record in the data table I need to still display the client name with a balance of zero on my table in my view. Need some direction on how to handle this. I was thinking I need to query my list of clients and loop through that query just not sure how to do it.
I want my view to look like below:
+-------------+---------+
| Client Name | Balance |
+-------------+---------+
| xxx | $75.00 |
| xxx | $100.00 |
| xxx | $0.00 |
+-------------+---------+
Here is a rough layout of the two tables in my database:
cj_clients
+----+-------------+
| id | client name |
+----+-------------+
| 1 | client1 |
| 2 | client2 |
| x | xxx |
+----+-------------+
cj_data
+----+-----------+-----------+
| id | client_id | job_total |
+----+-----------+-----------+
| 1 | 1 | 5.00 |
| 2 | 1 | 10.00 |
| 3 | 1 | 15.00 |
+----+-----------+-----------+
The below code returns the desired results except when no entries have yet been made to the cj_data table. Not sure how to still get the client in the table view with a balance of $0.
$this->db->select('client_name,client_id, sum(job_total) AS balance')
->from('cj_data')
->join('cj_clients','cj_data.client_id = cj_clients.id')
->group_by('client_name');
return $this->db->get()->result();
You need to give left join
$this->db->select('client_name,client_id, IFNULL(sum(job_total),0) AS balance')
->from('cj_data')
->join('cj_clients','cj_data.client_id = cj_clients.id',"left") // here
->group_by('client_name');
return $this->db->get()->result();
I wrote IFNULL condition if record not found or it will show all data for all clients in cj_clients
Note: the Default behaviour of CodeIgniter is it will add inner join
if join not specified
Hello I am facing hard time trying to realized this task. The problem is that I am not sure in which way this have to be proceeded and couldn't find tutorials or information about realizing this type of task.
The question is I have 2 tables and one connecting table between the two of them. With regular query usually what is displayed is the table header which is known value and them then data. In My case I have to display the table horizontally and vertically since the header value is unknown value.
Here is example of the DB
Clients:
+--------+------ +
| ID | client|
+--------+------ +
| 1 | Sony |
| 2 | Dell |
+--------+------ +
Users:
+--------+---------+------------+
| ID | name | department |
+--------+--------+-------------+
| 1 | John | 1|
| 2 | Dave | 2|
| 3 | Michael| 1|
| 4 | Rich | 3|
+--------+--------+-------------+
Time:
+--------+------+---------------------+------------+
| ID | user | clientid | time | date |
+--------+------+---------------------+------------+
| 1 | 1 | 1 | 01:00:00 | 2017-01-02 |
| 2 | 2 | 2 | 02:00:00 | 2017-01-02 |
| 3 | 1 | 2 | 04:00:00 | 2017-02-02 | -> Result Not Selected since date is different
| 4 | 4 | 1 | 02:00:00 | 2017-01-02 |
| 5 | 1 | 1 | 02:00:00 | 2017-01-02 |
+--------+------+---------------------+------------+
Result Table
+------------+--------+-----------+---------+----------+
| Client | John | Michael | Rich | Dave |
+------------+--------+-----------+---------+----------+
| Sony |3:00:00 | 0 | 2:00:00 | 0 |
+------------+--------+-----------+---------+----------+
| Dell | 0 | 0 | 0 | 2:00:00 |
+------------+--------+-----------+---------+----------+
First table Clients Contains information about clients.
Second table Users Contains information about users
Third Table Time contains rows of time for each users dedicated to different clients from the clients table.
So my goal is to make a SQL Query which will show the Result table. In other words it will select sum of hours which every user have completed for certain client. The number of clients and users is unknown. So first thing that have to be done is Select all users, no matter if they have hours completed or not. After that have to select each client and the sum of hours for each client which was realized for individual user.
The problem is I don't know how to approach this situation. Do I have first to make one query slecting all users then foreach them in the table header and then realize second query selecting the hours and foreaching the body conent, or this can be made with single query which will render the whole table.
The filters for select command are:
WHERE MONTH(`date`) = '$month'
AND YEAR(`date`) ='$year'
AND u.department = '$department'
Selecting single row for tume SUM is:
(SELECT SUM( TIME_TO_SEC( `time` ) ) FROM Time tm
WHERE tm.clientid = c.id AND MONTH(`date`) = '$month' AND YEAR(`date`) ='$year'
This is the query to select the times for a user , here by my logic this might be transformed with GROUP BY c.id (client id), and the problem is that it have to contains another WHERE clause which will specify the USER which is unknown. If the users was known value was for example 5, there is no problem to make 5 subsequent for each user WHERE u.id = 1, 2, 3 etc.
So here are the 2 major problems how to display in same query The users header and them select the sum of hours for each client corresponding the user.
Check out the result table hope to make the things clear.
Any suggestion or answer which can come to resolve this situation will be very helpful.
Thank you!
I have a web app in which I show a series of posts based on this table schema (there are thousands of rows like this and other columns too (removed as not required for this question)) :-
+---------+----------+----------+
| ID | COL1 | COL2 |
+---------+----------+----------+
| 1 | NULL | ---- |
| 2 | --- | NULL |
| 3 | NULL | ---- |
| 4 | --- | NULL |
| 5 | NULL | NULL |
| 6 | --- | NULL |
| 7 | NULL | ---- |
| 8 | --- | NULL |
+---------+----------+----------+
And I use this query :-
SELECT * from `TABLE` WHERE `COL1` IS NOT NULL AND `COL2` IS NULL ORDER BY `COL1`;
And the resultant result set I get is like:-
+---------+----------+----------+
| ID | COL1 | COL2 |
+---------+----------+----------+
| 12 | --- | NULL |
| 1 | --- | NULL |
| 6 | --- | NULL |
| 8 | --- | NULL |
| 11 | --- | NULL |
| 13 | --- | NULL |
| 5 | --- | NULL |
| 9 | --- | NULL |
| 17 | --- | NULL |
| 21 | --- | NULL |
| 23 | --- | NULL |
| 4 | --- | NULL |
| 32 | --- | NULL |
| 58 | --- | NULL |
| 61 | --- | NULL |
| 43 | --- | NULL |
+---------+----------+----------+
Notice that the IDs column is jumbled thanks to the order by clause.
I have proper indexes to optimize these queries.
Now, let me explain the real problem. I have a lazy-load kind of functionality in my web-app. So, I display around 10 posts per page by using a LIMIT 10 after the query for the first page.
We are good till here. But, the real problem comes when I have to load the second page. What do I query now? I do not want the posts to be repeated. And there are new posts coming up almost every 15 seconds which make them go on top(by top I literally mean the first row) of the resultset(I do not want to display these latest posts in the second or third pages but they alter the resultset size so I cannot use LIMIT 10,10 for the 2nd page and so on as the posts will be repeated.).
Now, all I know is the last ID of the post that I displayed. Say 21 here. So, I want to display the posts of IDs 23,4,32,58,61,43 (refer to the resultset table above). Now, do I load all the rows without using the LIMIT clause and display 10 ids occurring after the id 21. But for that I will have to interate over thousands of useless rows.But, I cannot use a LIMIT clause for the 2nd,3rd... pages that is for sure. Also, the IDs are jumbled, so I can definitely not use WHERE ID>.... So, where do we go now?
I'm not sure if I've understood your question correctly, but here's how I think I would do it:
Add a timestamp column to your table, let's call it date_added
When displaying the first page, use your query as-is (with LIMIT 10) and hang on to the timestamp of the most recent record; let's call it last_date_added.
For the 2nd, 3rd and subsequent pages, modify your query to filter out all records with date_added > last_date_added, and use LIMIT 10, 10, LIMIT 20, 10, LIMIT 30, 10 and so on.
This will have the effect of freezing your resultset in time, and resetting it every time the first page is accessed.
Notes:
Depending on the ordering of your resultset, you might need a separate query to obtain the last_date_added. Alternatively, you could just cut off at the current time, i.e. the time when the first page was accessed.
If your IDs are sequential, you could use the same trick with the ID.
Hmm..
I thought for a while and came up with 2 solutions. :-
To store the Ids of the post already displayed and query WHERE ID NOT IN(id1,id2,...). But, that would cost you extra memory. And if the user loads 100 pages and the ids are in 100000s then a single GET request would not be able to handle it. At least not in all browsers. A POST request can be used.
Alter the way you display posts from COL1. I don't know if this would be a good way for you. But, it can save you bandwith and make your code cleaner. It may also be a better way. I would suggest this :- SELECT * from TABLE where COL1 IS NOT NULL AND COL2 IS NULL AND Id>.. ORDER BY ID DESC LIMIT 10,10. This can affect the way you display your posts by leaps and bounds. But, as you said in your comments that you check if a post meets a criteria and change the COL1 from NULL to the current timestammp, I guess that the newer the posts the, the more above you want to display them. It's just an idea.
I assume new posts will be added with a higher ID than the current max ID right? So couldn't you just run your query and grab the current max ID. Then when you query for page 2 do the same query but with "ID < max_id". This should give you the same result set as your page 1 query because any new rows will have ID > max_id. Hope that helps?
How about?
ORDER BY `COL1`,`ID`;
This would always put IDs in order. This will let you use:
LIMIT 10,10
for your second page.
Lets say we have following tables
Table Pages:
id | short_name | long_name | token
1 | Mail | My mail box | mail
2 | All mails | All mails | all
3 | Inbox | Inbox only | inb
4 | Users | Users | users
5 | All users | All users | all
and table navigation:
id | parent_id | page_id
1 | 0 | 4
2 | 0 | 1
3 | 1 | 2
4 | 1 | 3
5 | 4 | 5
I was working with only page ids for a long time. It was easy to find details of page with only 1 value - $_GET['id'], because ids of pages all are unique.
Now, I want to create human readable (token based) navigation system.
But there is 1 problem. Tokens are not always unique.
For ex. index.php?page=mail&subpage=all and index.php?page=users&subpage=all
Can't figure out, how to find short_name and long_name (or other information of page) for these 2 pages (by 2 - $_GET['page'] and $_GET['subpage'] or more variables)?
Maybe I'm in wrong way. If you think so, please suggest your idea, and explain. Thx in advance.
Sorry if this doesn't work out of the box, but does this help?
SELECT * FROM Pages
JOIN navigation ON Pages.id=navigation.page_id
WHERE navigation.parent_id=(SELECT id FROM Pages WHERE token={$page})
AND Pages.token={$subpage}