Have not been able to find any information on this, I could do this in its own but I feel keeping it in the query might be the best option, if its possible.
Basically I want to try to add a top level "statistics" portion of a query.
So when I get the results I will see it like so
num_rows = 900
distinct_col = 9
results = array()
This way I can loop the results normally, and then pull out information that I would only need once outside of it. Is this possible?
EDIT:
I am not looking for the normal mysql statistics like num_rows exactly. But in a case where lets say you limit the results to ten, num_rows would return 10, but you want total results, so 900. In most cases I would just use another query and look just for the amount, however combining it all into one query logically seems faster for me. There is also more then just the num_rows I may need, say they are all products and have a specific category, I would need to count the amount of categories all items fall under. So looping the raw results when there is only one result for those columns is sillyness.
EDIT 2:
To clarify further I need to get some counts on some columns, and maybe a min-max result on a join. Having it return on every loop would work, but the same exact return uselessly returning on every loop when its only needed once does not seem logical. I am no MySQL expert and am mainly just trying to make sure I come up with the most logical and fastest method to get the required data.
Here is a PHP return example:
array(
[num_rows] => 900,
[categories] => 9,
[min_price] => 400,
[max_price] => 900,
[results] => array(
[0] => //row array
[1] -> //row array
)
);
Mysql returns its default num rows before you "fetch" the results, having custom results added there may be sufficient.
Dunno why do you need that but that's very easy to get
Assuming you are using safeMysql (though you can use whatever way to get data into array)
$results = $db->getAll("SELECT * FROM t");
$num_rows = count($results);
$num_cols = count($results[0]);
that's all
I am mainly just trying to make sure I come up with the most logical and fastest method to get the required data.
Yes, you are.
Nothing wrong with getting aggregated data with every loop.
As for the count beyond LIMITs - when you need it, you can use mysql's SQL_CALC_FOUND_ROWS / FOUND_ROWS() feature
Related
I have a view where user select fields to make an advance search, the fields are:
**name**- **age** - **location** - **isPaid** - **date_subscription**, **date_expiration**
the user might choose one column or make combinations of multiple columns, I am confused if I should use if statement to detect which columns are selected, and then run the query depends on the selected column, but this way I will need to set all the valid conditions, which mean set the all the valid combination. Is there an other way to execute such queries?
I was writing this query, but i stopped because i just realize how long it will be:
SELECT * FROM internetclientdetails icd INNER JOIN internetclient ic on ic.id = icd.icid WHERE
(icd.date_sub <=".$start_dateSubsc." and cd.date_sub >= ".$end_dateSubsc.")
OR
(icd.date_exp <=".$start_dateExp." and cd.date_exp >= ".$end_dateExp.")
OR
(
(icd.date_sub <=".$start_dateSubsc." and cd.date_sub >= ".$end_dateSubsc.")
AND
(icd.date_exp <=".$start_dateExp." and cd.date_exp >= ".$end_dateExp.")
)
OR
.
.
.
but this is too long to be write since i still have 4 left fields to set OR , AND operators
Generally you add some already query building library, which can construct valid SQL from the input you select.
There are a number of them, for example, Doctrine DB abstraction layer, Medoo and a number of others.
For example, in Medoo a rather complex query such as:
SELECT account,user_name FROM table
WHERE user_id IN (2,123,234,54) OR
email IN ('foo#bar.com','cat#dog.com','admin#medoo.in')
will be writen in PHP as:
$database->select("account", "user_name", [
"OR" => [
"user_id" => [2, 123, 234, 54],
"email" => ["foo#bar.com", "cat#dog.com", "admin#medoo.in"]
]
]);
So all you have to do when using medoo is to pass it the correct input from the form.
As regards your question about how the user selects different columns, you can use something like this:
$mapping=array("start_dateSubsc"=>"date_sub", "end_dateSubsc"=>"date_sub",...);
where you list all the possible fields for user to enter in webpage, which are mapped to the real database table column names.
Then you do something like this, when you process the page:
$wherequery["OR"]=array();
foreach ($mapping as $userfield => $dbfield)
{
if array_key_exists($userfield, $_REQUEST)
array_push($wherequery["OR"], $dbfield => $_REQUEST[$userfield]);
}
$database->select("your columns"),[ $wherequery ]);
This will work for fields that need to be = to what user said and where you must match any of the fields.
You would have a bit more to do with fields that can be in range, and process them seperately, as well as processing fields with "AND", but that depends on the range and possibilities of your actual fields.
I'm trying to set up an ability to get some numbers from my Sphinx indexes, but not sure how to get the info I want.
I have a mysql db with articles, sphinx index set up for that db and full text search, all working. What I want is to get some numbers:
How many times search text (keyword, or key phrase) appears over all articles for all time (more likely limited to "articles from time interval from X and to Y")
Same as previous but for how many times 2 keywords or keyphrases (so "x AND y") appear in same articles
I was doing something similar to first manually using bat file I made
indexer ind_core -c c:\%SOME_PATH%\development.sphinx.conf --buildstops stats.txt 10000 --buildfreqs
Which generated me a txt with all repeating keywords and how often they appear at early development stages, which helped to form a list of keywords I'm interested in. Now I'm trying to do the same but just for a finite list of predetermined keywords and integrated into my rails project to be able to build charts in future.
I tried running some queries like
#testing = Article.search 'Keyword1 AND Keyword2', :ranker => :wordcount
but I'm not sure how it works and how to process the result, as well as if that's what I'm looking for.
Another approach I tried was manual mysql queries such as
SELECT id,title,WEIGHT() AS w FROM ind_core WHERE MATCH('#title keyword1 | keyword2') OPTION ranker=expr('sum(hit_count)');
but I'm not sure how to process results from here either (as well as how to actually implement it into my existing rails project), and it's limited to 20 lines per query (which I think I can change somewhere in settings?). But at least looking at mysql results what I'm interested in is hit_count over all articles (or all articles from set timeframe).
Any ideas on how to do this?
UPDATE:
Current way I found was to add
#testing = Article.search params[:search], :without => {:is_active => false}, :ranker => :bm25
to controller with some conditions (so it doesn't bug out from nil search). :is_active is my soft delete flag, don't want to search deleted entries, so don't mind it. And in view I simply displayed
<%= #testing.total_entries %>
Which if I understand it correct shows me number of matches sphinx found (so pretty much what I was looking for).
So, to figure out the number of hits per document, you're pretty much on the right track, it's just a matter of getting it into Ruby/Thinking Sphinx.
To get the raw Sphinx results (if you don't need the ActiveRecord objects):
search = Article.search "foo",
:ranker => "expr('SUM(hit_count)')",
:select => "*, weight()",
:middleware => ThinkingSphinx::Middlewares::RAW_ONLY
… this will return an array of hashes, and you can use the weight() string key for the hit count, and the sphinx_internal_id string key for the model's primary key (id is Sphinx's own primary key, which isn't so useful).
Or, if you want to use the ActiveRecord objects, Thinking Sphinx has the ability to wrap each search result in a helper object which passes appropriate methods through to the underlying model instances, but lets weight respond with the values from Sphinx:
search = Article.search "foo",
:ranker => "expr('SUM(hit_count)')",
:select => "*, weight()"; ""
search.context[:panes] << ThinkingSphinx::Panes::WeightPane
search.each do |article|
puts article.weight
end
Keep in mind that panes must be added before the search is evaluated, so if you're testing this in a Rails console, you'll want to avoid letting the console inspect the search variable (which I usually do by adding ; "" at the end of the initial search call.
In both of these cases, as you've noted, the search results are paginated - you can use the :page option to determine which page of results you want, and :per_page to determine the number of records returned in each request. There is a standard limit of 1000 results overall, but that can be altered using the max_matches setting.
Now, if you want the number of times the keywords appear across all Sphinx records, then the best way to do that while also taking advantage of Thinking Sphinx's search options, is to get the raw results of an aggregate SUM - similar to the first option above.
search = Article.search "foo",
:ranker => "expr('SUM(hit_count)')",
:select => "SUM(weight()) AS count",
:middleware => ThinkingSphinx::Middlewares::RAW_ONLY
search.first["count"]
Disclaimer I'm self taught. Got my rudimentary knowledge of php reading forums. I'm an sql newb, and know next to nothing about yii.
I've got a controller that shows the products on our webstore. I would like the out of stock products to show up on the last pages.
I know I could sort by stock quantity but would like the in stock products to change order every time the page is reloaded.
My solution (probably wrong but kinda works) is to run two queries. One for the product that has stock, sorted randomly. One for the out of stock product also ordered randomly. I then merge the two resulting arrays. This much has worked using the code below (although I feel like there must be a more efficient way than running two queries).
The problem is that this messes up the pagination. Every product returned is listed on the same page and changing pages shows the same results. As far as I can tell the pagination only works for 1 CDbCriteria at a time. I've looked at the yii docs for CPagination for a way around this but am not getting anywhere.
$criteria=new CDbCriteria;
$criteria->alias = 'Product';
$criteria->addCondition('(inventory_avail>0 OR inventoried=0)');
$criteria->addCondition('Product.parent IS NULL');
$criteria->addCondition('web=1');
$criteria->addCondition('current=1');
$criteria->addCondition('sell>sell_web');
$criteria->order = 'RAND()';
$criteria2=new CDbCriteria;
$criteria2->alias = 'Product';
$criteria2->addCondition('(inventory_avail<1 AND inventoried=1)');
$criteria2->addCondition('Product.parent IS NULL');
$criteria2->addCondition('web=1');
$criteria2->addCondition('current=1');
$criteria2->addCondition('sell>sell_web');
$criteria2->order = 'RAND()';
$crit1=Product::model()->findAll($criteria);
$crit2=Product::model()->findAll($criteria2);
$models=array_merge($crit1,$crit2);
//I know there is something wrong here, no idea how to fix it..
$count=Product::model()->count($criteria);
$pages=new CPagination($count);
//results per page
$pages->pageSize=30;
$pages->applyLimit($criteria);
$this->render('index', array(
'models' => $models,
'pages' => $pages
));
Clearly I am in over my head. Any help would be much appreciated.
Edit:
I figured that a third CDbCriteria that includes both the in stock and out of stock items could be used for the pagination (as it would include the same number of products as the combined results of the first 2). So I tried adding this (criteria1 and criteria2 remain the same):
$criteria3=new CDbCriteria;
$criteria3->alias = 'Product';
//$criteria3->addCondition('(inventory_avail>0 OR inventoried=0)');
$criteria3->addCondition('Product.parent IS NULL');
$criteria3->addCondition('web=1');
$criteria3->addCondition('current=1');
$criteria3->addCondition('sell>sell_web');
//$criteria3->order = 'RAND()';
$crit1=Product::model()->findAll($criteria);
$crit2=Product::model()->findAll($criteria2);
$models=array_merge($crit1,$crit2);
$count=Product::model()->count($criteria3);
$pages=new CPagination($count);
//results per page
$pages->pageSize=30;
$pages->applyLimit($criteria3);
$crit1=Product::model()->findAll($criteria);
$crit2=Product::model()->findAll($criteria2);
$models=array_merge($crit1,$crit2);
$this->render('index', array(
'models' => $models,
'pages' => $pages
));
I'm sure I'm missing something super obvious here... Been searching all day getting nowhere.
So you are running into what is IMO one of the potential drawbacks of natural language query builder frameworks. They can get your thinking on how you might approach a SQL problem going down a bad path when trying to work with the "out of the box" methods for building queries. Sometimes you might need to think about using raw SQL query capabilities that most every framework to provide in order to best address your problem.
So let's start with the basic SQL for how I would suggest you approach your problem. You can either work this into your query builder style (if possible) or make a raw query.
You could easily form a calculated field representing binary inventory status for sorting. Then also sort by another criteria secondarily.
SELECT
field1,
field2,
/* other fields */
IF(inventory_avail > 0, 1, 0) AS in_inventory
FROM product
WHERE /* where conditions */
ORDER BY
in_inventory DESC, /* sort items in inventory first */
other_field_to_sort ASC /* other sort criteria */
LIMIT ?, ? /* pagination row limit and offset */
Note that this approach only returns the rows of data you need to display. You move away from your current approach of doing a lot of work in the application to merge record sets and such.
I do question use of RAND() for pagination purposes as doing so will yield products potentially appearing on one page after another as the user paginates through the pages, with other products perhaps not showing up at all. Either that or you need to have some additional complexity added to your applicatoin to somehow track the "randomized" version of the entire result set for each specific user. For this reason, it is really unusual to see order randomization for paginated results display.
I know you mentioned you might like to spike out a randomized view to the user on a "first page". If this is a desire that is OK, but perhaps you decouple or differentiate that specific view from a wider paginated view of the product listing so as to not confuse the end user with a seemingly unpredictable pagination interface.
In your ORDER BY clause, you should always have enough sorting conditions to where the final (most specific) condition will guarantee you a predictable order result. Oftentimes this means you have to include an autoincrementing primary key field, or similar field that provides uniqueness for the row.
So let's say for example I had the ability for user to sort items by price, but you still obviously wanted to show all inventoried items first. Now let's say you have 100K products such that you will have many "pages" of products with a common price when ordered by price
If you used this for ordering:
ORDER BY in_inventory DESC, price ASC
You could still have the problem of a user seeing the same product repeated when navigating between pages, because a more specific criteria than price was not given and ordering beyond that criteria is not guaranteed.
You would probably want to do something like:
ORDER BY in_inventory DESC, price ASC, unique_id ASC
Such that the order is totally predictable (even though the user may not even know there is sorting being applied by unique id).
When I query some view in Couchbase I get the response that has following structure:
{
"total_rows":100,
"rows":[...]
}
'total_rows' is very useful property that I can use for paging.
But lets say I select only a subset of view using 'start_key' and 'end_key' and of course I don't know how big this subset will be. 'total_rows' is still the same number (as I understand it's just total of whole view). Is there any easy way to know how many rows was selected in subset?
You can use the in-built reduce function _count to get the total count of your query.
Just add _count as reduce function for your view. After that, you will need to make two calls to couchbase:
In one call, you'll set the query param reduce=true (along with either group=true or group_level=n, depending upon how you're sending your key(s)). This will give you the total count of your filtered rows.
In the other call, you'll disable the reduce function with reduce=false because you now need the actual rows.
You can find more details about map and reduce at http://docs.couchbase.com/admin/admin/Views/views-writing.html
You can just use an array count/total/length in whatever language you are using.
For example in PHP:
$result = $cb->view("dev_beer", "beer_by_name", array('startkey' => 'O', 'endkey'=>'P'));
echo "total = >>".count($result["rows"])
If you're actually wanting to paginate your data then you should use limit and skip:
http://www.couchbase.com/docs/couchbase-manual-2.0/couchbase-views-writing-querying-pagination.html
If you have to paginate the view in the efficient way, you actually don't need to specify both start and the end.
Generally it is possible to use startkey/startkey_id and limit. In this case the limit will tell you that the page won't be bigger than known size.
Both cases are described in CouchDB book: http://guide.couchdb.org/draft/recipes.html#pagination
Here is how it works:
Request rows_per_page + 1 rows from the view
Display rows_per_page rows, store + 1 row as next_startkey and next_startkey_docid
As page information, keep startkey and next_startkey
Use the next_* values to create the next link, and use the others to create the previous link
I am looking at this.
I have queries that return up to 10,000 rows and usually fills up the memory
I am currently doing:
$this->db->get()->result_array();
Is there a way to not load all of the data into memory and use some sort of cursor? It seems result and result array are both arrays. (one is array of objects other is an array of arrays)
If you are using Active Record, which I would personally recommend, limit() should achieve what you are looking for.
$this->db->limit();
Can also use in this way, slightly easier and less lines of code:
$query = $this->db->get('Table_Name', 50); //syntax db->get('Table',limit_val);
return $query->result();
Also can return a limit with an offset:
$this->db->limit(10, 20); // Second parameter lets you set a result offset
Link for more help on Active Record Query's
https://www.codeigniter.com/userguide2/database/active_record.html#select
Mysql offset is the pointer you are looking for.
You can use it like:
$this->db->get(tableName,10,20);
The second parameter and the third one help you to set limit and offset .
Here are more details