SQL Select Statement

SQL SELECT Statement

The SELECT statement is one of the most commonly used commands in SQL. It is used to retrieve data from one or more tables in a database. You can specify the columns you want to retrieve or use a wildcard (*) to select all columns.

Syntax

The basic syntax of the SELECT statement is:


SELECT column1, column2, ...
FROM table_name;

To retrieve all columns:


SELECT * FROM table_name;

Example

Let us retrieve all columns from the Staff table and then retrieve specific columns (ID and Name).

Code Example


-- Retrieve all columns from the Staff table
SELECT * FROM Staff;

-- Retrieve specific columns: ID and Name
SELECT ID, Name FROM Staff;

Output

-- SELECT * FROM Staff:

ID	Name	Age	Department
1	Alice	30	HR
2	Bob	25	IT
3	Charlie	35	Finance

-- SELECT ID, Name FROM Staff:

ID	Name
1	Alice
2	Bob
3	Charlie

Explanation

- The first SELECT * query retrieves all the columns from the Staff table.
- The second SELECT ID, Name query retrieves only the ID and Name columns.
- The output demonstrates the retrieved rows based on the queries.

- Use SELECT * only when you need all columns; otherwise, explicitly specify the columns to improve performance.
- Ensure the table exists and contains the required data before executing the SELECT statement.