Executing SQL Queries Using SELECT Statements

In SQL, the SELECT statement is used to retrieve data from one or more tables in a database. It allows you to specify the columns to retrieve from a table. Here’s an overview of the basic SELECT statement.

SELECT Syntax

The basic syntax of a SELECT statement is as follows:

SELECT column1, column2, ...
FROM table_name;

column1, column2, …: Specifies the columns to retrieve from the table.
table_name: Specifies the table from which to retrieve the data.

If you want to retrieve all the columns from a table, you would use “*” symbol:

SELECT *
FROM table_name;

By using the SELECT statement, you can retrieve specific data from a database table. The result set will contain the specified columns for all the rows in the table.

By default, the SELECT statement retrieves all rows from the table, including duplicate rows. If you want to retrieve only unique rows, you can use the DISTINCT keyword.

SELECT DISTINCT column1, column2, ...
FROM table_name;

Let’s say we have a table named “employees” with columns “employee_id,” “first_name,” and “last_name.” To retrieve all the employee IDs, first names, and last names from this table, we would use the following SELECT statement:

SELECT employee_id, first_name, last_name
FROM employees;

This statement will fetch the employee_id, first_name, and last_name columns from the “employees” table, returning the data for all rows.

The SELECT statement is fundamental in SQL as it allows you to retrieve data from tables. By specifying the desired columns, you can customize the result set to meet your specific requirements.