How to execute an SQL query and fetch results using PHP ?
In this article, we will discuss how to execute an SQL query and how to fetch its result?
We can perform a query against the database using the PHP mysqli_query() method.
Syntax: We can use the mysqli_query( ) method in two ways:
- Object-oriented style
- Procedural style
Parameters:
- connection: It is required that specifies the connection to use.
- query: It is also required that specifies the database query.
- result mode: It is optional to use.
Return value: For SELECT, SHOW, DESCRIBE, or EXPLAIN it returns a mysqli_result object. For other successful queries, it returns true. Otherwise, it returns false on failure.
Let's understand how we can execute an SQL query.
Executing an SQL query: We will understand how we can execute an SQL query with an example. We will create a database, table and then insert some values into it.
Example: Create a database and insert some values into it.
<?php
$servername = "localhost";
$username = "root";
$password = "";
$conn = new mysqli($servername, $username, $password);
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
$sql = "CREATE DATABASE gfgDB";
if ($conn->query($sql) === TRUE) {
echo "Database has been created successfully";
} else {
echo "Error creating database: " . $conn->error;
}
$conn->close();
?>
Output:
Database has been created successfully
Creating the table:
<?php
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "gfgDB";
$conn = new mysqli($servername, $username, $password, $dbname);
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
$sql = "CREATE TABLE Emp (
id INT(6) AUTO_INCREMENT PRIMARY KEY,
firstname VARCHAR(30) NOT NULL,
lastname VARCHAR(30) NOT NULL
)";
if ($conn->query($sql) === TRUE) {
echo "Table has been created successfully";
} else {
echo "Error creating table: " . $conn->error;
}
$conn->close();
?>
Output:
Table has been created successfully
Inserting some values into the table "Emp":
<?php
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "gfgDB";
$conn = new mysqli($servername, $username, $password, $dbname);
if ($conn->connect_error){
die("Connection failed: " . $conn->connect_error);
}
$sql = "INSERT INTO Emp (firstname, lastname)
VALUES ('XYZ', 'ABC')";
if ($conn->query($sql) === TRUE) {
echo "New record created successfully";
}else{
echo "Error: " . $sql . "<br>" . $conn->error;
}
$conn->close();
?>
Output:
New record created successfully
Note: Since we have used AUTO_INCREMENT, it will automatically insert the record with "id=1" and for each newly inserted record, it will increase the "id" by one.
Fetching results from the database:
<?php
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "gfgDB";
$conn = new mysqli($servername, $username, $password, $dbname);
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
$sql = "SELECT id, firstname, lastname FROM Emp";
$result = $conn->query($sql);
if ($result->num_rows > 0) {
while($row = $result->fetch_assoc()) {
echo "id: " . $row["id"]. " - Name: "
. $row["firstname"]. " " . $row["lastname"]. "<br>";
}
}
else {
echo "No records has been found";
}
$conn->close();
?>
Output:
id: 1 - Name: XYZ ABC
