Pdo php left join

How to handle LEFT OUTER JOIN results efficiently with PHP / PDO

How to keep pee from splattering from the toilet all around the basin and on the floor on old toilets that are really low and have deep water? ,I could loop through my array of existing event objects and check if the id already exists when going through the resultset, but this seems a little inefficient. Is there a more elegant solution, possibly built into PDO?,And parse results into array: //$queryResult is the result returned by your query while($row = $queryResult->fetch(PDO::FETCH_ASSOC)) < $results[$row['event']][] = $row['person']; >,Now I’m somewhat stuck with looping though the results. I want to create event objects from the results, but I want one event only as one object, adding attendees to it.

Slightly modify your query (now we have different names for event name and person name):

SELECT events.id, events.name as event, people.id, people.name as person FROM events LEFT OUTER JOIN attendees ON events.id = attendees.e_id LEFT OUTER JOIN people ON attendees.p_id = people.id

Answer by Harold Cameron

PDOStatement::fetchAll — Returns an array containing all of the result set rows ,PDOStatement::fetchColumn() — Returns a single column from the next row of a result set,PDOStatement::fetch() — Fetches the next row from a result set,Example #1 Fetch all remaining rows in a result set

Fetch all of the remaining rows in the result set: Array ( [0] => Array ( [name] => apple [0] => apple [colour] => red [1] => red ) [1] => Array ( [name] => pear [0] => pear [colour] => green [1] => green ) [2] => Array ( [name] => watermelon [0] => watermelon [colour] => pink [1] => pink ) ) 

Answer by Bianca Dillon

Loop through the result set using the fetch() method of the PDOStatement object and process each row individually.,See the following getProjects() method.,See the following getTasks() method.,The following getProjectObjectList() method returns a list of project objects.

See the following getProjects() method.

.wp-block-code < border: 0; padding: 0; >.wp-block-code > div < overflow: auto; >.shcb-language < border: 0; clip: rect(1px, 1px, 1px, 1px); -webkit-clip-path: inset(50%); clip-path: inset(50%); height: 1px; margin: -1px; overflow: hidden; padding: 0; position: absolute; width: 1px; word-wrap: normal; word-break: normal; >.hljs < box-sizing: border-box; >.hljs.shcb-code-table < display: table; width: 100%; >.hljs.shcb-code-table > .shcb-loc < color: inherit; display: table-row; width: 100%; >.hljs.shcb-code-table .shcb-loc > span < display: table-cell; >.wp-block-code code.hljs:not(.shcb-wrap-lines) < white-space: pre; >.wp-block-code code.hljs.shcb-wrap-lines < white-space: pre-wrap; >.hljs.shcb-line-numbers < border-spacing: 0; counter-reset: line; >.hljs.shcb-line-numbers > .shcb-loc < counter-increment: line; >.hljs.shcb-line-numbers .shcb-loc > span < padding-left: 0.75em; >.hljs.shcb-line-numbers .shcb-loc::before < border-right: 1px solid #ddd; content: counter(line); display: table-cell; padding: 0 0.75em; text-align: right; -webkit-user-select: none; -moz-user-select: none; -ms-user-select: none; user-select: none; white-space: nowrap; width: 1%; >/** * Get all projects * @return type */ public function getProjects() < $stmt = $this->pdo->query('SELECT project_id, project_name ' . 'FROM projects'); $projects = []; while ($row = $stmt->fetch(\PDO::FETCH_ASSOC)) < $projects[] = [ 'project_id' =>$row['project_id'], 'project_name' => $row['project_name'] ]; > return $projects; >Code language: PHP (php)

This method retrieves all projects from the projects table using the following SELECT statement.

SELECT project_id, project_name FROM projects;Code language: SQL (Structured Query Language) (sql)

Second, we called the fetch() method of the PDOStatement object to retrieve the next row from the result set. We passed the following value to the fetch_style parameter of the fetch() method.

\PDO::FETCH_ASSOCCode language: PHP (php)

The following getProjectObjectList() method returns a list of project objects.

 /** * Get the project as an object list * @return an array of Project objects */ public function getProjectObjectList() < $stmt = $this->pdo->query('SELECT project_id, project_name ' . 'FROM projects'); $projects = []; while ($project = $stmt->fetchObject()) < $projects[] = $project; >return $projects; >Code language: PHP (php)

Note that the property names of the object correspond to the column names in the result set. For example, you can access the property names of the project object as:

$project->project_id; $project->project_name;Code language: PHP (php)

See the following getTasks() method.

 /** * Get tasks by the project id * @param int $projectId * @return an array of tasks in a specified project */ public function getTaskByProject($projectId) < // prepare SELECT statement $stmt = $this->pdo->prepare('SELECT task_id, task_name, start_date, completed_date, completed, project_id FROM tasks WHERE project_id = :project_id;'); $stmt->execute([':project_id' => $projectId]); // for storing tasks $tasks = []; while ($row = $stmt->fetch(\PDO::FETCH_ASSOC)) < $tasks[] = [ 'task_id' =>$row['task_id'], 'task_name' => $row['task_name'], 'start_date' => $row['start_date'], 'completed_date' => $row['completed_date'], 'completed' => $row['completed'], 'project_id' => $row['project_id'], ]; > return $tasks; >Code language: SQL (Structured Query Language) (sql)

See the following getTaskCountByProject() method that returns the number of tasks in a specified project.

 /** * Get the number of tasks in a project * @param int $projectId * @return int */ public function getTaskCountByProject($projectId) < $stmt = $this->db->prepare('SELECT COUNT(*) FROM tasks WHERE project_id = :project_id;'); $stmt->bindParam(':project_id', $projectId); $stmt->execute(); return $stmt->fetchColumn(); >Code language: PHP (php)

Answer by Kaden Jaramillo

It is also possible to GROUP BY a database expression:,Less than: $people = ORM::for_table(‘person’)->where_lt(‘age’, 10)->find_many();,Greater than: $people = ORM::for_table(‘person’)->where_gt(‘age’, 5)->find_many();,Less than or equal: $people = ORM::for_table(‘person’)->where_lte(‘age’, 10)->find_many();

where('name', 'Fred Bloggs')->find_one(); // PSR-1 compliant style $person = ORM::forTable('person')->where('name', 'Fred Bloggs')->findOne(); 

Answer by Jeremiah Harper

Underneath the covers, the query builder uses PDO prepared statements which protect against SQL injection attacks.,Alternatively, you can express nested associations using the dot notation:,This function will not load any columns from the specified associations into the result set.,It is also possible to restrict deeply-nested associations using the dot notation:

use Cake\ORM\TableRegistry; // Prior to 3.6 use TableRegistry::get('Articles') $articles = TableRegistry::getTableLocator()->get('Articles'); // Start a new query. $query = $articles->find(); 

Answer by Camryn Salazar

If your join expression is “Table_1 NATURAL JOIN Table_2”, the effect is the same as if you specified “Table_1 NATURAL INNER JOIN Table_2” – so non-matching rows won’t be part of the result Table.,Oracle uses “WHERE Table_1.column (+) = Table_2.column” for a LEFT OUTER JOIN.,A theta-join is any Cartesian product that’s filtered by a condition which compares values from both Tables. That is, the general theta-join form is:,There is also a FULL [OUTER] JOIN, for situations when there might be missing information from both joined Tables. This is rarely used.

 ::= CROSS JOIN | [ NATURAL ] [ ] JOIN [ ] | ( ) ::= INNER | [ OUTER ] | UNION ::= ON | USING (join [ <,join > . ]) 

Answer by Miguel Shields

To remove a mapped record from our table, invoke the erase() method on an auto-hydrated data mapper. For example:,F3 keeps track of all commands issued to the underlying SQL database driver, as well as the time it takes for each statement to complete — just the right information you need to tweak application performance.,If you ever want to find out which SQL statements issued directly by your application (or indirectly thru mapper objects) are causing performance bottlenecks, you can do so with a simple:,Your application code becomes simple because it does not have to maintain two mapper objects (one for the projects table and another for users) just to retrieve data from two joined tables:

Establishing communication with a SQL engine like MySQL, SQLite, PostgreSQL, SQL Server, Sybase, and Oracle is done using the familiar $f3->set() command. Connecting to a SQLite database would be:

$f3->set('DB', new DB\SQL('sqlite:/absolute/path/to/your/database.sqlite'));

Another example, this time with MySQL:

$db=new DB\SQL( 'mysql:host=localhost;port=3306;dbname=mysqldb', 'admin', 'p455w0rD' );

Let’s continue our PHP code:

$f3->set('result',$db->exec('SELECT brandName FROM wherever')); echo Template::instance()->render('abc.htm');

This time we create an HTML template like abc.htm that has at a minimum the following:

Here’s another example. Instead of a single statement provided as an argument to the $db->exec() command, you can also pass an array of SQL statements:

$db->exec( array( 'DELETE FROM diet WHERE food="cola"', 'INSERT INTO diet (food) VALUES ("carrot")', 'SELECT * FROM diet' ) );

Answer by Evelyn Baker

There is no special DQL keyword that distinguishes a regular join from a fetch join. A join (be it an inner or outer join) becomes a fetch join as soon as fields of the joined entity appear in the SELECT part of the DQL query outside of an aggregate function. Otherwise its a regular join.,How can i paginate fetch-joined collections?,Retrieve a CmsUser and fetch join all the phonenumbers it has:,Why does pagination not work correctly with fetch joins?

Here is an example that selects all users with an age > 20:

1createQuery('SELECT u FROM MyProject\Model\User u WHERE u.age > 20'); $users = $query->getResult(); 2 3

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