開発スタッフがアプリ関連の最新技術やニュースをご紹介します。

Today I will talk about some common aggregate functions that are widely used in SQL programming language.

Count

if we want to get the count of all records or specific where condition records, we can get by using count function.

SELECT COUNT(column_name) FROM table_name
SELECT COUNT(column_name) FROM table_name WHERE condition;

AVG

For average rate calculations, we can use this.

SELECT AVG(column_name) FROM table_name;
SELECT AVG(column_name) FROM table_name WHERE condition;

SUM

For sum results of all records, we can use this.

SELECT SUM(column_name) FROM table_name 
SELECT SUM(column_name) FROM table_name WHERE condition;

MIN

For specific minimum result of a column, we can use this.

SELECT MIN(column_name) FROM table_name;
SELECT MIN(column_name) FROM table_name WHERE condition;

Likewise min, we can use max to get maximum result.

SELECT MAX(column_name) FROM table_name;
SELECT MAX(column_name) FROM table_name WHERE condition;

By Yuuma

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ルーティングとは「ブラウザで入力されたURL」(リクエストURL)と、Laravelのコントローラを紐付ける方法です。

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Today I will talk about how to operate Json data in PHP especially using json_encode & json_decode.

So, Lets get started. We have an array like this.

<?php
$months = array("Jan"=>"01","Feb"=>"02","March"=>"03","April"=>"04");
?>

If we want to change that array to json format, we can do like this.

<?php
$months = array("Jan"=>"01","Feb"=>"02","March"=>"03","April"=>"04");

echo json_encode($months);
?>

So What about decoding, decoding the also similar with encoding.

<?php
$json = '{"Jan":"01","Feb":"02","March":"03","April":"04"}';

//we can treat the decoded data in two ways (object & array)
//treating like an object.
$obj = json_decode($json);
echo $obj->Jan;

// treating like an array
$array = json_decode($json,true);
echo $array['Jan'];
?>

The sample concept if you want to loop through the decoded json.

<?php
$json = '{"Jan":"01","Feb":"02","March":"03","April":"04"}';

$array = json_decode($jsonobj, true);

foreach($array as $key => $value) {
  echo $key . " => " . $value . "<br>";
}

<?php
$json = '{"Jan":"01","Feb":"02","March":"03","April":"04"}';

$obj = json_decode($jsonobj);

foreach($obj as $key => $value) {
  echo $key . " => " . $value . "<br>";
}

By Yuuma

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今回はLaravelの「シーダー」(Seeder)機能を使用して初期データの投入をおこなう方法を紹介します。

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I will talk about file operations in PHP( handling , read, write etc.). Lets take a look at reading file first.

As an example we have a file called test.txt and if we want to read the contents within the file, can simply do like this.

<?php
echo readfile("test.txt");
//this will out put the contents within the file
?>

But what if we want to handle more than reading a file, we can use fopen

<?php

//we have to open the file first along with the operation mode.
//(r,w,a,x) etc. you can see more detail as below. 
// https://www.php.net/manual/en/function.fopen.php
$file = fopen("test.txt", "r") or die("Unable to open file!");
//then we read the file by specifying maximum number of bytes to read
echo fread($file,filesize("test.txt"));
// then simply close the file.
fclose($file);
?>

We can also get the first line in file using fgets

<?php
$file = fopen("test.txt", "r") or die("Unable to open file!");
echo fgets($file);
fclose($file);
?>

We can also use feof to check whether the file reaches to the end.

<?php
$file = fopen("test.txt", "r") or die("Unable to open file!");
// Output until end-of-file
while(!feof($file)) {
  echo fgets($file) . "<br>";
}
fclose($file);
?>

If we want to check whether file exists or not , we can do like this

<?php
echo file_exists("test.txt");
//if exists, it will return 1
?>

By Yuuma.

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