SQL Reference

Example

CREATE TABLE Employees (
    EmployeeID INT,
    FirstName VARCHAR(255),
    LastName VARCHAR(255)
);

INSERT INTO Employees (EmployeeID, FirstName, LastName)
VALUES (1, 'John', 'Doe');

SELECT * FROM Employees;

Output

+------------+-----------+----------+
| EmployeeID | FirstName | LastName |
+------------+-----------+----------+
|          1 | John      | Doe      |
+------------+-----------+----------+

Explanation

In the example above, an Employees table is created with the EmployeeID column of INT data type, and the FirstName and LastName columns of VARCHAR data type. One new record is inserted into the Employees table where the EmployeeID is 1, the FirstName is John and the LastName is Doe. The * in the SELECT statement indicates that all rows of the Employees table are displayed in the output.

Example

CREATE TABLE Employees (
    ID INT,
    NAME TEXT
);

INSERT INTO Employees (ID, NAME)
VALUES (1, 'John Doe');

SELECT * FROM Employees;

Output

 ID |   NAME
----|----------
  1 | John Doe

Explanation

In the above example, an Employees table is created with two columns: ID and NAME. The ID column is declared as INT to hold integer values representing the unique identifiers for each record. A record is inserted into the table with ID being 1 and NAME being John Doe. The final SELECT statement displays all records in the Employees table where the ID is an integer.

Example

DECLARE @TestINT INT;
SET @TestINT = 20;
SELECT @TestINT AS TestValue;

Output

TestValue
20

Explanation

In the example, we declare a variable ‘@TestINT’ of INT type and assign it a value of 20. The SELECT statement is then used to output the value of ‘@TestINT’, which is 20.

Example

CREATE TABLE Person (
    ID INT PRIMARY KEY,
    FirstName VARCHAR(100),
    LastName VARCHAR(100)
);

INSERT INTO Person (ID, FirstName, LastName)
VALUES (1, 'John', 'Doe');

Output

Statement processed.
1 row created.

Explanation

The data type INT is used for integer values. In the example, ID is a data column with the integer (INT) data type. It stores the primary key for each record in the Person table. After the table is successfully created, we insert one row with the ID value of 1.

Example

CREATE TABLE Employees (
    ID INT PRIMARY KEY,
    Name TEXT NOT NULL,
    Age INT NOT NULL
);

INSERT INTO Employees (ID, Name, Age)
VALUES (1, 'John Doe', 32);

SELECT * FROM Employees;

Output

ID | Name     | Age
---| -------- | ---
1  | John Doe | 32

Explanation

In the example code, a table called ‘Employees’ is created with three columns: ID, Name, and Age. The INT data type is used for both the ID, which is declared as the primary key, and the Age. Then, an employee with ID 1, name ‘John Doe’, and age 32 is inserted into the table. The final command selects and outputs all records from the ‘Employees’ table.