Explain Retrieval queries in SQL

Retrieval queries in SQL are used to fetch data from one or more tables in a database. They are typically constructed using the SELECT statement, which allows you to specify the columns to retrieve, the tables from which to retrieve them, and any conditions that the retrieved data must meet.

example of a retrieval query in SQL:

SELECT column1, column2
FROM table_name
WHERE condition;

• SELECT is used to specify the columns to retrieve.
• FROM specifies the table from which to retrieve the data.
• WHERE is used to specify any conditions that the retrieved data must meet (optional).

For example, to retrieve all columns from a table named employees where the department is ‘Sales’, you would use the following query:

SELECT *
FROM employees
WHERE department = 'Sales';

You can also use functions like COUNT, SUM, AVG, MIN, and MAX to perform calculations on retrieved data. For example, to get the total number of employees in the employees table, you would use:

SELECT COUNT(*)
FROM employees;