SQL AND & OR

The AND/OR operators are used to create an SQL statement based on 2 or more conditions in SQL WHERE clause. They can be used in SELECT, UPDATE, DELETE or INSERT statement.

The AND operator selects records if all the conditions in WHERE clause are true at the same time. The OR operator selects records if any conditions in the WHERE clause are true.

Syntax

SELECT columns
FROM tables
WHERE condition1
     {[AND|OR] condition2}+

The {}+ means that we can repeat it one or more times.

Note: We can indicate the order of the conditions by using the parenthesis sign ().

Examples

Table: Employees

EmployeeId	FirstName	LastName	Department	Salary
203	Mazojys	Fxoj	Finance	78000
204	Jozzh	Lnanyo	Finance	45800
205	Syllauu	Dfaafk	Finance	57000
206	Gecrrcc	Srlkrt	Finance	62000
302	Jssme	Bdnaa	Development	75000
303	Dnnaao	Errllov	Development	55000
304	Tyoysww	Osk	Development	49000

Example 1
We want to select an employee whose first name is Syllauu and last name is Dfaafk:

SELECT *
FROM Employees
WHERE FirstName='Syllauu' AND LastName='Dfaafk'

The result will look like:

EmployeeId	FirstName	LastName	Department	Salary
205	Syllauu	Dfaafk	Finance	57000

Example 2
We want to select employees whose last name is Lnanyo or Bdnaa:

SELECT *
FROM Employees
WHERE LastName='Lnanyo' OR LastName='Bdnaa'

The result will look like:

EmployeeId	FirstName	LastName	Department	Salary
204	Jozzh	Lnanyo	Finance	45800
302	Jssme	Bdnaa	Development	75000

Example 3
Now we put a little bit more conditions:

SELECT *
FROM Employees
WHERE Department='Finance' AND (LastName='Lnanyo' OR LastName='Bdnaa')

The result will look like:

EmployeeId	FirstName	LastName	Department	Salary
204	Jozzh	Lnanyo	Finance	45800