Why displaying array when select column in mysql? - php

Question

I am trying to select a column in mysql in php,
function PageController() {
$data = [
'categories' => _db_get_select("categories", ['name'])
];
load_view("tutu", $data);
and
function _db_get_select($table_name, $columns) {
$servername = _c("database.server_name");
$username = _c("database.username");
$password = _c("database.password");
$dbname = _c("database.db_name");
$conn = mysqli_connect($servername, $username, $password, $dbname);
if (!$conn) {
die("Connection failed: " . mysqli_connect_error());
}
// echo "Connected successfully";
$sql = "SELECT name=$columns FROM . $table_name.";
var_dump($sql);
the result is displaying like this
string(42) "SELECT ['name']=Array FROM . categories."
I want to be like this
SELECT name FROM . categories.
Thanks in advance.

Answer 1

You may use this script
function PageController() {
$data = [
'categories' => _db_get_select("categories", "name")
];
load_view("tutu", $data);
And the function will be
function _db_get_select($table_name, $columns) {
$servername = _c("database.server_name");
$username = _c("database.username");
$password = _c("database.password");
$dbname = _c("database.db_name");
$conn = mysqli_connect($servername, $username, $password, $dbname);
if (!$conn) {
die("Connection failed: " . mysqli_connect_error());
}
$sql = "SELECT {$columns} FROM {$table_name}";
}

Answer 2

Just echo your sql variable instead of var dump like below
echo $sql;

Answer 3

Use foreach loop to iterate through an array of columns to form a query.
function PageController() {
$data = array('categories' => _db_get_select("categories", array("name")));
load_view("tutu", $data);
}
And then:
//Start with select
$sql = 'SELECT ';
//Concat column names separated with commas
foreach ($columns as $value) {
$sql .= $value . ', ';
}
//Get rid of the last comma
$sql = rtrim($sql, ', ');
$sql .= ' FROM ' . $table_name;
Check if it's okey:
var_dump($sql);