SQL Basics

SQL Basics

Table of Contents

Create and Check Connection

				
					$servername = "localhost";
$username = "saurabh";
$password = "123456";
$dbname = "bapugraphics";

// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);

// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
} 
echo "Connected successfully
";
				
			

Delete

				
					DELETE Customer

WHERE Id = 17

DELETE Product

WHERE Price > 100
				
			

FETCH Result

Run Show Query

				
					if ($result->num_rows > 0) {
    // output data of each row
    while($row = $result->fetch_assoc()) {
        echo "<h2>".$row["username"]. "</h2>".
        $row["email"]. "<br>".
        $row["mobile"]. "<br>---------------------------<br>";
    }
} else {
    echo "0 results";
}
				
			

INSERT

INSERT INTO table-name (column-names)

VALUES (values)

				
					INSERT INTO Customer (FirstName, LastName, City, Country, Phone)

VALUES ('Saurabh', 'Chugh', 'Delhi', 'India', 9898000000)
				
			

Run Query

				
					$sql = "INSERT INTO regform (username, password, email, mobile, address, dateofbirth)
VALUES ('$username', '$password', '$email', '$mobile', '$address', '$dateofbirth')"
;
$result = $conn->query($sql);
				
			

OFFSET FETCH

Problem: Get all but the 10 most expensive products sorted by price

				
					SELECT Id, ProductName, UnitPrice, Package

FROM Product

ORDER BY UnitPrice DESC

OFFSET 10 ROWS
				
			

Problem: Get the 10th to 15th most expensive products sorted by price

				
					SELECT Id, ProductName, UnitPrice, Package

FROM Product

ORDER BY UnitPrice DESC

OFFSET 10 ROWS

FETCH NEXT 5 ROWS ONLY
				
			

ORDER BY

				
					SELECT CompanyName, ContactName, City, Country

FROM Supplier

ORDER BY CompanyName
				
			
				
					SELECT CompanyName, ContactName, City, Country

FROM Supplier

ORDER BY CompanyName DESC
				
			
				
					SELECT FirstName, LastName, City, Country

FROM Customer

ORDER BY Country, City
				
			
				
					SELECT Id, CompanyName, City, Country

FROM Supplier

WHERE Country IN ('USA', 'Japan', 'Germany')

ORDER BY Country ASC, CompanyName DESC
				
			
				
					SELECT Id, OrderDate, CustomerId, TotalAmount

FROM [Order]

ORDER BY YEAR(OrderDate) ASC, TotalAmount DESC
				
			

SELECT and WHERE

				
					SELECT *

FROM table-name
				
			
				
					SELECT *

FROM Customer


				
			
				
					SELECT FirstName, LastName, City

FROM Customer
				
			
				
					SELECT Id, FirstName, LastName, City, Country, Phone

FROM Customer

WHERE Country = 'India'
				
			
				
					Run Select Query

$sql = "SELECT * FROM registrationform where gender='$gender'";
$result = $conn->query($sql);
				
			

Select Database from Form

				
					// select database
$username=$_POST["username"];
$password=$_POST["password"];
$email=$_POST["email"];
$mobile=$_POST["mobile"];
$address=$_POST["address"];
$dateofbirth=$_POST["dateofbirth"];
				
			

SELECT TOP

Problem: List top 10 most expensive products

				
					SELECT TOP 10 Id, ProductName, UnitPrice, Package

FROM Product

ORDER BY UnitPrice DESC
				
			

UPDATE

UPDATE regform

				
					SET City = 'Pune', Phone = '9876543210', email = 'abc@gmail.com'

WHERE Id = 15
				
			

UPDATE regform

				
					SET City = 'Noida'

WHERE Name = 'Saurabh
				
			

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