Introduction to MySQL SELECT FROM statement

The SELECT statement allows you to select data from one or more tables. To write a SELECT statement in MySQL, you use this syntax:

SELECT 
   column1,
   column2,
   column3...
FROM 
   Table_name;

In this syntax:

• First, specify one or more columns from which you want to select data after the SELECTkeyword. If the SELECT  has multiple columns, you need to separate them by a comma (,).
• Second, specify the name of the table from which you want to select data after the FROMkeyword.
• The semicolon (;) is optional, which denotes the end of a statement. If you have two or more statements, you need to use the semicolon(;) to separate them so that MySQL will execute each statement individually.

1. Using the SELECT FROM statement to retrieve data from a single column example

Using the  employees table that has eight columns: employeeNumber, lastName, firstName, extension, email, officeCode, reportsTo, and jobTitle.. The following example uses the SELECT FROM statement to retrieve the last names of all employees:

SELECT lastName
FROM employees;

The result of a SELECT statement is called a result set as it’s a set of rows that results from the query.

2. Using the SELECT FROM statement to query data from multiple columns example

The following example uses the SELECT FROM statement to get the first name, last name, and job title of employees:

SELECT
   lastName,
   firstName,
   jobTitle
FROM
   employees;

3. Using the SELECT FROM statement to retrieve data from all columns example

If you want to select data from all the columns of the employees table, you can specify all the column names in the SELECT clause like this:

SELECT 
   employeeNumber,
   lastName,
   firstName,
   extension,
   email,
   officeCode,
   eportsTo,
   jobTitle
FROM   
   employees;

Alternatively, you can use the asterisk (*) which is the shorthand for all columns. For example:

SELECT *
FROM employees;

The query returns data from all the columns of the employees table. The SELECT * is often called “select star” or “select all” since it selects data from all columns of the table. In practice, you should use the SELECT * for the ad-hoc queries only.