In zend framework 1, we had used mysql rand() function like below or using zend_db_expr(). I have tried this in ZF2, but this is not working. Somebody please help me to use this in Zend Framework 2
$select = $this->db()->select()
->from('TABLE')
->order('RAND()');
Thanks,
Looking at the API it appears that the order function accepts a string or array of parameters order(string | array $order). My first thought was to use a key/val array. However, as I look at the actual code of the Db\Sql\Select, the string or array that you are passing gets quoted (see here). Assuming that your Db platform is Mysql, this is the function that quotes the fields (see here). It appears to iterate through each of the fields, and add these quotes, rendering your rand() function a useless string.
Getting to the point, the solution is up to you, but it does not appear that you can do it the way you want with this current version of ZF2.
You will need to extend the Db\Sql\Select class, OR extend the Db\Adapter\Platform\Mysql class, OR change the code in these classes, OR execute your query as a full select statement, OR change up your logic.
By changing up your logic I mean, for example, if your table has an Integer primary key, then first select the MAX(id) from the table. Then, choose your random numbers in PHP prior to executing your query like $ids[] = rand(1, $max) for as many results as you need back. Then your sql logic would look like SELECT * FROM table WHERE id IN(453, 234, 987, 12, 999). Same result, just different logic. Mysql's rand() is very "expensive" anyways.
Hope this helps!
Here you can use \Zend\Db\Sql\Expression. Example function from ModelTable:
public function getRandUsers($limit = 1){
$limit = (int)$limit;
$resultSet = $this->tableGateway->select(function(Select $select) use ($limit){
$select->where(array('role' => array(6,7), 'status' => 1));
$rand = new \Zend\Db\Sql\Expression('RAND()');
$select->order($rand);
$select->limit($limit);
//echo $select->getSqlString();
});
return $resultSet;
}
Related
I have quite an issue I can not seem to solve. I am trying to get a row count from a select statement.
I should start by saying I have tried most all methods resulting from google searches on this issue.
I am using the result set so I would prefer not to make a second query.
The query uses a prepared select statement which seems to be a main issue if I understand it correctly.
I decided to try a simple approach using PHP's native count() function. Which lead me here because I finally reached the end of the rope on this.
On to the details...within a class of mine, I make the query like this.
// Create database connection
$database = DatabaseFactory::getFactory()->getConnection();
// Set and execute database query
$sql = "SELECT * FROM `service_orders` WHERE `agency_id` = :agency_id $filter ORDER BY $sort $order $per_page";
$query = $database->prepare($sql);
$query->execute($query_array);
// If results
if ($query->rowCount() > 0) {
$results = $query->fetchAll();
self::$order_count = "Count: " . count($results);
return $results;
}
// Default, return false
return false;
Findings
If I perform count($results) like I did above, I get the total rows in the database (Let's say 50).
If I print_r($results), it shows the array with the proper number of entries (Let's say 10) that of course differs from the total rows in the database.
How can these two differ? It's as if the count($results) is misreading the result array.
More Findings
Within my actual php page, I call the class to retrieve the data like this.
$results = OrderModel::getServiceOrders();
echo count($results);
Strangely enough, if I then perform count($results) it gives me the correct reading of the result array (which in my example here would be 10).
I am perplexed by this as the count function is being performed on the exact same array. The only difference is one is called on the array within the class, and the other is called on the array returned from the class.
Does anyone have any ideas on how to solve this or why there is the discrepancy when using count() in this instance?
Thank you all in advance!
James
Additional Info
This is another mind numbing scenario. If I return the count along with the actual results, I can access it on the page with the correct value (10 rows). Yet, if I set it into a session variable, and access it that way, the count is the whole data set (50 rows). How is it even possible these two values are not the same?!
$results = $query->fetchAll();
Session::set("order_count", $total[0]); // Yields 50 (incorrect)
return [
"results"=> $results,
"count"=> $total[0], // Yields 10 (correct)
];
I'm working on cakePHP 3. I have a user defined function(UDF or Routine) in mysql database. That function takes a parameter and returns an integer value. I have to order that returned value in MySQL order clause.
I know mysql query to use that function. i.e,
SELECT customer_id FROM table_name ORDER BY routine_name(param1); //param1 is 'customer_id' which I have written after SELECT
But I don't know that how to build this query in cakePHP 3. If anyone knows the solution, answer will be appreciate.
Here is my cakePHP 3 code.
$purchasesTable = TableRegistry::get("Purchases");
$query = $purchasesTable->find();
$sf_val = $query->func()->routine_name(['Purchases.customer_id' => 'literal']);
$query->select();
$query->order(
// Routine/Function call should be here as per MySQL query.
// So, I think here I have to do something.
);
I'd suggest that you have a closer look at the (API) docs, it's all mentioned there. You can pass expression objects to Query::order(), and in case you need to specify the direction, there's also Query::orderAsc() and Query::orderDesc().
So
$expression = $query->func()->routine_name(['Purchases.customer_id' => 'literal']);
$query->order($expression);
or
$query->orderAsc($expression);
or
$query->orderDesc($expression);
See also
Cookbook > Database Access & ORM > Query Builder > Selecting Data
API > \Cake\Database\Query::order()
API > \Cake\Database\Query::orderAsc()
API > \Cake\Database\Query::orderDesc()
In CakePHP3, there is a ORM that helps with building queries.
From the documentation, I can see that
$query = $articles->find(); // build a query that has not run yet
$query->where(['id' => 1]); // Return the same query object
So in this case, I want the string
WHERE `articles`.`id` = 1
After much googling, I found out that there is a way to return just the where clause of a query object.
$query->where(['id' => 1])->clause('where'); // Return the where clause in the form of a QueryExpression
More googling leads me to find out how to get the QueryExpression to spit out string representation
$query->where(['id' => 1])->clause('where')->sql($valueBinder); // Return the where clause in string format
Here is my problem. I don't know what the $valueBinder is supposed to look like. I don't know how to initialize it.
I am also happy not to use ValueBinder as long as I can get the where clause in string format using CakePHP 3 ORM and in the right SQL dialect. Please assume I am using MySQL.
Please advise.
EDIT
I tried to use $query->valueBinder() as the $valueBinder.
It is empty and does not contain the associated c:0 to the value 1.
To directly answer your question, you can get the SQL for any clause this way:
$binder = new \Cake\ORM\ValueBinder();
$query->clause('where')->sql($binder);
That will return the SQL with the correct placeholders, not with the values to be used. The values live in the $binder variable and are used for statement objects.
As I can see, you only wanted to preserve the internal structure of the where clause to pass it to another query in a different request. Your solution is fine, but I'd like to add that you can also encode a full conditions tree from an existing query:
$where = serialize($query->clause('where'));
$anotherQuery->where(unserialize($where)); // A query in another request
In any case, you need to be careful with what you are unserializing as taking it directly from user input will certainly lead to security problems.
You can choose to omit this param if you like. Please see http://api.cakephp.org/3.0/class-Cake.Database.Query.html#_sql
In addition, you can use the Query member function traverse($visitor, $parts) to isolate the where clause. $visitor is a function that takes a value and a clause. You define the behavior of $visitor. $parts is an array of clause names. I suggest passing array('where') into this param.
My workaround is that I store the conditions in json string format.
Using the same example, what I do is
$data['conditions'] = json_encode(['Articles.id' => 1]); // encode into JSON string
$this->DynamicRules->patchEntity($dynamicRule, $data); // use in edit action of DynamicRulesController
then when I need to reuse the conditions, I do:
$articlesTable = TableRegistry::get('Articles');
$query = $articlesTable->find(); // new query for Articles
$rule = json_decode($dynamicRule->conditions, true); // get back the conditions in associative array format
$query->where($rule); // re-assign the conditions back
This got me what I ultimately wanted.
I have table of dogs in my DB and I want to retrieve N latest added dogs.
Only way that I found is something like this:
Dogs:all()->where(time, <=, another_time);
Is there another way how to do it? For example something like this Dogs:latest(5);
Thank you very much for any help :)
You may try something like this:
$dogs = Dogs::orderBy('id', 'desc')->take(5)->get();
Use orderBy with Descending order and take the first n numbers of records.
Update (Since the latest method has been added):
$dogs = Dogs::latest()->take(5)->get();
My solution for cleanliness is:
Dogs::latest()->take(5)->get();
It's the same as other answers, just with using built-in methods to handle common practices.
Dogs::orderBy('created_at','desc')->take(5)->get();
You can pass a negative integer n to take the last n elements.
Dogs::all()->take(-5)
This is good because you don't use orderBy which is bad when you have a big table.
You may also try like this:
$recentPost = Article::orderBy('id', 'desc')->limit(5)->get();
It's working fine for me in Laravel 5.6
I use it this way, as I find it cleaner:
$covidUpdate = COVIDUpdate::latest()->take(25)->get();
Ive come up with a solution that helps me achieve the same result using the array_slice() method. In my code I did array_slice( PickupResults::where('playerID', $this->getPlayerID())->get()->toArray(), -5 ); with -5 I wanted the last 5 results of the query.
The Alpha's solution is very elegant, however sometimes you need to re-sort (ascending order) the results in the database using SQL (to avoid in-memory sorting at the collection level), and an SQL subquery is a good way to achieve this.
It would be nice if Laravel was smart enough to recognise we want to create a subquery if we use the following ideal code...
$dogs = Dogs::orderByDesc('id')->take(5)->orderBy('id')->get();
...but this gets compiled to a single SQL query with conflicting ORDER BY clauses instead of the subquery that is required in this situation.
Creating a subquery in Laravel is unfortunately not simply as easy as the following pseudo-code that would be really nice to use...
$dogs = DB::subQuery(
Dogs::orderByDesc('id')->take(5)
)->orderBy('id');
...but the same result can be achieved using the following code:
$dogs = DB::table('id')->select('*')->fromSub(
Dogs::orderByDesc('id')->take(5)->toBase(),
'sq'
)->orderBy('id');
This generates the required SELECT * FROM (...) AS sq ... sql subquery construct, and the code is reasonably clean in terms of readability.)
Take particular note of the use of the ->toBase() function - which is required because fromSub() doesn't like to work with Eloquent model Eloquent\Builder instances, but seems to require a Query\Builder instance). (See: https://github.com/laravel/framework/issues/35631)
I hope this helps someone else, since I just spent a couple of hours researching how to achieve this myself. (I had a complex SQL query builder expression that needed to be limited to the last few rows in certain situations).
For getting last entry from DB
$variable= Model::orderBy('id', 'DESC')->limit(1)->get();
Imagine a situation where you want to get the latest record of data from the request header that was just inserted into the database:
$noOfFilesUploaded = count( $request->pic );// e.g 4
$model = new Model;
$model->latest()->take($noOfFilesUploaded);
This way your take() helper function gets the number of array data that was just sent via the request.
You can get only ids like so:
$model->latest()->take($noOfFilesUploaded)->puck('id')
use DB;
$dogs = DB::select(DB::raw("SELECT * FROM (SELECT * FROM dogs ORDER BY id DESC LIMIT 10) Var1 ORDER BY id ASC"));
Dogs::latest()->take(1)->first();
this code return the latest record in the collection
Can use this latest():
$dogs = Dogs::latest()->take(5)->get();
I'm developing an API for Cakephp where I pass some query parameters from a controller to another. These query must be arbitrary and could be related to several different models but the interesting result is always an integer.
The problem is that CakePHP always return an array with a different structure and keys for this array are always different.
How can I access the value I need or simplify the query to return a simple value?
I think you should look at Set::extract and rewrite the name of your fields in an unified way
<?
$res = $this->Model->query('select Model.myfield as myint from mytable Model');
$res = Set::extract( "/Model/myint", $res );
// $res = array( 0 => "value 1", ...);
see http://book.cakephp.org/view/1501/extract
or play a bit with array_shift to extract the first value in a loop.
hope this help. L