Salah satu kelemahan SQL adalah tidak mengenal "sistem koordinat" dimana : Show
Kedua sifat di atas sangat pentinguntuk menghasilkan dataset yang bersifat analisis. Namun untuk penomoran baris di MySQL kita memiliki solusi dengan trik penggunaan variable. Berikut adalah contoh penggunaannya : Penomoran Baris dengan VariableSELECT @nomorbaris:=@nomorbaris+1 AS nomorbaris, dan penggunaan lebih lanjut Penggunaan pada SubquerySELECT T1.Currency1, T1.Currency2, T1.Start_Date, T2.Start_Date AS End_Date, T1.Rate FROM Gampang bukan ? Nah, buat Anda yang mungkin masih baru dengan penggunaan variable di MySQL dapat melihat artikel saya disini. Dan untuk Anda yang ingin mengambil table yang sama dengan contoh di atas, dapat mengambilnya di halaman "Daftar Download Script SQL" dengan nama exchange_rate.sql. There are several ways to generate query results: This method returns the query result as an array of objects, or an empty array on failure. Typically you’ll use this in a foreach loop, like this: The above method is an alias of You can pass in the string ‘array’ if you wish to get your results as an array of arrays: <?php $query = $db->query('YOUR QUERY'); foreach ($query->getResult('array') as $row) { echo $row['title']; echo $row['name']; echo $row['body']; } The above usage is an alias of You can also pass a string to <?php $query = $db->query('SELECT * FROM users;'); foreach ($query->getResult('User') as $user) { echo $user->name; // access attributes echo $user->reverseName(); // or methods defined on the 'User' class } The above method is an alias of getResultArray()This method returns the query result as a pure array, or an empty array when no result is produced. Typically you’ll use this in a foreach loop, like this: <?php $query = $db->query('YOUR QUERY'); foreach ($query->getResultArray() as $row) { echo $row['title']; echo $row['name']; echo $row['body']; } Result RowsgetRow()This method returns a single result row. If your query has more than one row, it returns only the first row. The result is returned as an object. Here’s a usage example: <?php $query = $db->query('YOUR QUERY'); $row = $query->getRow(); if (isset($row)) { echo $row->title; echo $row->name; echo $row->body; } If you want a specific row returned you can submit the row number as a digit in the first parameter: <?php $row = $query->getRow(5); You can also add a second String parameter, which is the name of a class to instantiate the row with: <?php $query = $db->query('SELECT * FROM users LIMIT 1;'); $row = $query->getRow(0, 'User'); echo $row->name; // access attributes echo $row->reverse_name(); // or methods defined on the 'User' class getRowArray()Identical to the above <?php $query = $db->query('YOUR QUERY'); $row = $query->getRowArray(); if (isset($row)) { echo $row['title']; echo $row['name']; echo $row['body']; } If you want a specific row returned you can submit the row number as a digit in the first parameter: <?php $row = $query->getRowArray(5); In addition, you can walk forward/backwards/first/last through your results using these variations:
By default they return an object unless you put the word “array” in the parameter:
Note All the methods above will load the whole result into memory (prefetching). Use getUnbufferedRow()This method returns a single result row without prefetching the whole result in memory as <?php $query = $db->query('YOUR QUERY'); while ($row = $query->getUnbufferedRow()) { echo $row->title; echo $row->name; echo $row->body; } For use with MySQLi you may set MySQLi’s result mode to <?php $db->resultMode = MYSQLI_USE_RESULT; // for unbuffered results $query = $db->query('YOUR QUERY'); $file = new \CodeIgniter\Files\File(WRITEPATH . 'data.csv'); $csv = $file->openFile('w'); while ($row = $query->getUnbufferedRow('array')) { $csv->fputcsv($row); } $db->resultMode = MYSQLI_STORE_RESULT; // return to default mode Note When using You can optionally pass ‘object’ (default) or ‘array’ in order to specify the returned value’s type: <?php $query->getUnbufferedRow(); // object $query->getUnbufferedRow('object'); // object $query->getUnbufferedRow('array'); // associative array Custom Result ObjectsYou can have the results returned as an instance of a custom class instead of a Example: <?php class User { public $id; public $email; public $username; protected $last_login; public function lastLogin($format) { return $this->lastLogin->format($format); } public function __set($name, $value) { if ($name === 'lastLogin') { $this->lastLogin = DateTime::createFromFormat('U', $value); } } public function __get($name) { if (isset($this->{$name})) { return $this->{$name}; } } } In addition to the two methods listed below, the following methods also can take a class name to return the results as: getCustomResultObject()Returns the entire result set as an array of instances of the class requested. The only parameter is the name of the class to instantiate. Example: <?php $query = $db->query('YOUR QUERY'); $rows = $query->getCustomResultObject('User'); foreach ($rows as $row) { echo $row->id; echo $row->email; echo $row->last_login('Y-m-d'); } getCustomRowObject()Returns a single row from your query results. The first parameter is the row number of the results. The second parameter is the class name to instantiate. Example: <?php $query = $db->query('YOUR QUERY'); $row = $query->getCustomRowObject(0, 'User'); if (isset($row)) { echo $row->email; // access attributes echo $row->last_login('Y-m-d'); // access class methods } You can also use the Example: <?php $row = $query->getCustomRowObject(0, 'User'); Result Helper MethodsgetFieldCount()The number of FIELDS (columns) returned by the query. Make sure to call the method using your query result object: <?php $query = $db->query('SELECT * FROM my_table'); echo $query->getFieldCount(); getFieldNames()Returns an array with the names of the FIELDS (columns) returned by the query. Make sure to call the method using your query result object: <?php $query = $db->query('SELECT * FROM my_table'); echo $query->getFieldNames(); getNumRows()The number of records returned by the query. Make sure to call the method using your query result object: <?php $query = $db->query('SELECT * FROM my_table'); echo $query->getNumRows(); Note Because SQLite3 lacks an efficient method returning a record count, CodeIgniter will fetch and buffer the query result records internally and return a count of the resulting record array, which can be inefficient. freeResult()It frees the memory associated with the result and deletes the result resource ID. Normally PHP frees its memory automatically at the end of script execution. However, if you are running a lot of queries in a particular script you might want to free the result after each query result has been generated in order to cut down on memory consumption. Example: <?php $query = $thisdb->query('SELECT title FROM my_table'); foreach ($query->getResult() as $row) { echo $row->title; } $query->freeResult(); // The $query result object will no longer be available $query2 = $db->query('SELECT name FROM some_table'); $row = $query2->getRow(); echo $row->name; $query2->freeResult(); // The $query2 result object will no longer be available dataSeek()This method sets the internal pointer for the next result row to be fetched. It is only useful in combination with It accepts a positive integer value, which defaults to 0 and returns true on success or false on failure. <?php $query = $db->query('SELECT `field_name` FROM `table_name`'); $query->dataSeek(5); // Skip the first 5 rows $row = $query->getUnbufferedRow(); Note Not all database drivers support this feature and will return false. Most notably - you won’t be able to use it with PDO. Class ReferenceclassCodeIgniter\Database\ BaseResult getResult ([$type =
'object'])
A wrapper for the Usage: see Result Arrays. getResultArray ()
Returns the query results as an array of rows, where each row is itself an associative array. Usage: see Result Arrays. getResultObject ()
Returns the query results as an array of rows, where each row is an object of type Usage: see Result Arrays. getCustomResultObject ($class_name)
Returns the query results as an array of rows, where each row is an instance of the specified class. getRow ([$n = 0[, $type = 'object']])
A wrapper for the Usage: see Result Rows. getUnbufferedRow ([$type =
'object'])
Fetches the next result row and returns it in the requested form. Usage: see Result Rows. getRowArray ([$n =
0])
Returns the requested result row as an associative array. Usage: see Result Rows. getRowObject ([$n =
0])
Returns the requested result row as an object of type Usage: see Result Rows. getCustomRowObject ($n, $type)
Returns the requested result row as an instance of the requested class. dataSeek ([$n = 0])
Moves the internal results row pointer to the desired offset. Usage: see Result Helper Methods. setRow ($key[, $value =
null])
Assigns a value to a particular column. getNextRow ([$type = 'object'])
Returns the next row from the result set. getPreviousRow ([$type = 'object'])
Returns the previous row from the result set. getFirstRow ([$type = 'object'])
Returns the first row from the result set. getLastRow ([$type = 'object'])
Returns the last row from the result set. getFieldCount ()
Returns the number of fields in the result set. Usage: see Result Helper Methods. getFieldNames ()
Returns an array containing the field names in the result set. getFieldData ()
Generates an array of getNumRows ()
Returns number of rows returned by the query freeResult ()
Frees a result set. Usage: see Result Helper Methods. |