I have a large amount of data that I'd like to be able to read out, pixel by pixel, into a Hilbert Curve using PHP's GD library.
The aim is to create a lookup table of an arbitrary size mapping an address to a point on a pixel grid. eg.
0 1 2 3
+-------------
0 | 0 1 14 15 ->
1 | 3 2 13 12
2 | 4 7 8 11
3 | 5 6 9 10
The eighth sequential address in this example would be 2,2. The end-result lookup table will just consist of points that can be referenced from.
1 - 0,0
2 - 0,1
3 - 1,1
4 - 0,2
I realise there is most certainly an effective way to generate this, I just haven't thought of it yet.
Related
Need some help in ranking poll options, tried doing by multidimensional arrays but nothing worked.
My data structure is as per below:
**Table** Poll
**Id** **Question** **op1** p1 **op2** p2 **op3** p3 **op4** p4 **op5** p5
1 q1 ? Excellent 5 Better 4 Good 3 Ok 2 Not OK 1
2 q2 ? Sure 5 Perfect 4 Fine 3 Never 2 No 1
**Table** Answer
**id** **poll_id** **users_id** **answer** **resultOrder**
---------------------------------------------------------------
1 1 1 Excellent 1
2 1 1 Better 2
3 1 1 Ok 3
4 1 1 Good 4
5 1 1 Not Ok 5
6 1 2 Excellent 1
7 1 2 Ok 2
8 1 2 Better 3
9 1 2 Not Ok 4
10 1 2 Good 5
Each user will submit five options priorities them as per his suggestion
Option will get ranking as per counts
e.g Excellent selected for 2 times for first preference it will get 100 points and others will get 80,60,40,20 points based on their counts for all priorities.
if count ties matches points will be given on p1, p2 column in table poll
**For Example if my group by [answer] look like below 5 people voted Excellent as first preference, 4 people voted better as second preference and so on till Not Ok preferred by 1 person for fifth preference **
Answer count(answer) it should set point like this
Excellent 5 100
Better 4 80
Good 3 60
Ok 2 40
Not Ok 1 20
Hope this is possible. I tried it many ways, but no luck.
I am developing a Lucky draw concept as following
There will be multiple options at database we have to get the random options according to percentage of appearance
Database table is as following
option_id | option_name | option_type | option_in_day(%) | option_status
----------------------------------------------------------------------
1 $2 Off 2 100 1
2 $3 Off 2 95 1
3 $4 Off 2 95 1
4 $5 Off 2 90 1
5 $8 Off 2 90 1
6 $60 Cashback 2 10 1
7 $100 Cashback 2 5 1
8 Umbrela 2 50 1
9 Iphone 2 2 1
10 International
Tour 2 1 1
11 Fidget
Spinner 2 70 1
12 Free
membership 2 30 1
13 Samsung S8 2 10 1
14 $20 Off 2 60 1
15 Travel Card 2 50 1
16 Soft Toys 2 70 1
Now from this table I want to get random 8 option according to percentage.
Less percentage option chance to retrieve in result will be less.
I have tried with random function in sql but can't reach the requirement.
This is how you should be able to do it:
set #percentage = 100 * rand();
select *
from table_name
order by table_name.percentage >= #percentage, rand()
limit 0, 8;
This query stores a random percentage into a variable. Then, we order the query by two criterias. The first criteria is that the percentage of the table is higher or equal to the percentage randomized. This makes sure that if there are elements both above and below the randomized percentage, then the elements above will be preferred. Elements having similar result in the first ordering criteria will be randomly ordered.
id company_id company_name size_of_company employee
-------------------------------------------------------------------
1 1 Comp 1 Big John
2 1 Comp 1 Big Ann
3 1 Comp 1 Big Peter
4 2 Comp 2 Big Lisa
5 2 Comp 2 Big Steve
6 3 Comp 3 Big Mike
7 3 Comp 3 Big Anna
8 3 Comp 3 Big Jon
9 3 Comp 3 Big Nick
10 3 Comp 3 Big May
11 4 Comp 4 Big Lee
12 4 Comp 4 Big James
13 4 Comp 4 Big Jess
14 4 Comp 4 Big Carrie
15 5 Comp 5 Big Luke
16 5 Comp 5 Big Brad
17 5 Comp 5 Big Joan
18 5 Comp 5 Big Ruth
19 5 Comp 5 Big Joel
20 6 Comp 6 Big Paul
This is probably an easy question, but my skills are quite low when it comes to MySQL and PHP. I have tried different loops with no result at all. Any help would be much appreciated.
What I want to do is this:
How do I count the amount of rows with the same company_id and size_of_company and then collect the amount of rows for the top 5 along with the names of the top 5 companies?
The amount of rows will be used in a div as width value for the div. The div shall be printed 5 times with different width value. The more rows the bigger div.
There will also be values of Medium and Small in size_of_company. But a company_name can only have one size_of_company. These two other size_of_company shall also be printed on the page, under their own category, Medium or Small.
If I understand the question correctly, the following would count the number of rows with the same company_id, company_name and size_of_company (using GROUP BY). Ordering and then limiting the number of results gives you the top 5.
SELECT
t.company_id,
t.company_name,
COUNT(*)
FROM
tble t
GROUP BY
t.company_id, t.company_name, t.size_of_company
ORDER BY
COUNT(*) DESC
LIMIT 5
OK – need some help here – might have bitten off more than I can chew here – but I’m looking to write a SQL query that always returns a minimum of 10 results. If the first condition is applied and the result set exceeds 10 results then move on to the next condition etc..
Example
Find all the small red plastic toy cars that cost less than £5.00.
I always want to show a minimum of 10 items on the screen. Want to search on “small” then on “red” and then on “< £5.00”. If the query returns more than 10 items then continue to filter on as many tags as possible (i.e plastic, toy and car) – the more matches it can make the higher it should be ranked (i.e if a products has all 3 tags associated with it – it will be at the top of the list, if a product only matches 1 tag – then this will be lower down the list.
Price Table
ID Price
1 £1.50
2 £2.50
3 £6.00
.
Colour Table
ID Colour
1 Red
2 Blue
3 Yellow
.
Size Table
ID Shape
1 Small
2 Medium
3 Large
.
Products Table
ID Description price_id colour_id size_id
1 Item 1 1 2 2
2 Item 2 2 2 1
3 Item 3 1 1 1
4 Item 4 3 2 3
5 Item 5 3 1 2
6 Item 6 1 1 2
7 Item 7 1 1 3
.
Tags Table
ID Description
1 Shiny
2 Plastic
3 Wood
4 Toy
5 Disney
6 Animal
7 Car
.
Items_Tags Table
ID tag_id product_id
1 1 1
2 4 1
3 7 1
4 2 2
5 3 3
6 4 3
7 7 6
8 7 7
9 7 2
Quite a long example - but I hope you get the point. I have wondered whether there would be any benefit to putting all the filters within the tags table - i.e the price, colour and size and then would only have to search against the tags table.
Any ideas anyone?
Thanks
It depends on your usage: filtering integers is faster than string (by the way, are they indexed?) but JOIN is also time consuming. So if the code outside the sql works with the integers, keep them (and don't join if not required to show the text)
I have a problem trying to apply rules about direct matches in a football[soccer] app. I have read this tread and it was very heplful on creating the standing positions table by the points criteria, difference and scored goals.
But i would like to know if is possible to order the teams position by direct matches:
look this positions table:
Pos Team Pld W D L F A GD Pts
1 FC Barcelona 5 2 3 0 8 5 3 9
2 **Inter Milan** 6 2 2 2 11 10 1 8
3 *Real Madrid* 6 2 2 2 8 8 0 8
4 AC Milan 5 0 3 2 8 12 -4 3
As you may see Inter Milan and Real Madrid are tied by points, and the Inter is heading real madrid because its goal difference. The result that i want to get is this :
Pos Team Pld W D L F A GD Pts
1 FC Barcelona 5 2 3 0 8 5 3 9
2 **Real Madrid** 6 2 2 2 8 8 0 8
3 *Inter Milan* 6 2 2 2 11 10 1 8
4 AC Milan 5 0 3 2 8 12 -4 3
Notice that in this time the real madrid is in front the inter milan because it won the two direct matches between them.
i have a table for teams and other for the results.
I would like to achive this using a query in mysql if is possible. Or maybe it would be better if i do this ordering on the server side (PHP).
Thanks any help would be appreciated.
It is impossible to efficiently do what you request in a single query that would return the results you ask for and sort the ties in points with that criteria.
The reasoning is simple: lets assume that you could get a column in your query that would provide or help with the kind of sorting you want. That is to say, it would order teams that are tied in points according to which one has more victories over the others (as this is very likely to happen to more than 2 teams). To make that calculation by hand you would need a double-entry table that shows the amount of matches won between those teams as follows:
| TeamA | TeamB | TeamC
------------------------------
TeamA | 0 | XAB | XAC
TeamB | XBA | 0 | XBC
TeamC | XCA | XCB | 0
So you would just add up each column row and sorting in descending order would provide you the needed data.
The problem is that you don't know which teams are tied before you actually get the data. So creating that column for the general case would mean you need to create the whole table of every team against every team (which is no small task); and then you need to add the logic to the query to only add up the columns of a team against those that are tied with it in points... for which you need the original result set (that you should be creating with the same query anyhow).
It may be possible to get that information in a single query, but it will surely be way too heavy on the DB. You're better off adding that logic in code afterwards getting the data you know you will need (getting the amount of games won by TeamA against TeamB or TeamC is not too complicated). You would still need to be careful about how you build that query and how many you run; after all, during the first few games of a league you will have lots of teams tied up against each other so getting the data will effectively be the same as building the whole double-entry table I used as an example before for all teams against all teams.
create temporary in a stored procedure and call to procedure...
create temporary table tab1 (position int not null auto_increment ,
team_name varchar(200),
points int,
goal_pt int,
primary key(position));
insert into tab1(team_name,
points,
goal_pt)
select team_name,
points,
goal_pt
from team
order by points desc,
goal_pt desc ;