SQL SELECT DISTINCT Statement
The SELECT DISTINCT
statement in SQL is used to return unique values from a specified column or combination of columns in a table. It eliminates duplicate records and displays only unique values.
Here is the basic syntax for the SELECT DISTINCT
statement:
SELECT DISTINCT column1, column2, ...
FROM table_name;
Example Table
Let's assume we have the following table named Employees
:
ID |
Name |
Department |
1 |
John |
Sales |
2 |
Jane |
Marketing |
3 |
John |
Sales |
4 |
Alice |
HR |
5 |
Bob |
Sales |
6 |
Jane |
Marketing |
Query to Get Unique Departments
To get a list of unique departments from the Employees
table, you can use the following query:
SELECT DISTINCT Department
FROM Employees;
Output:
Department |
Sales |
Marketing |
HR |
Query to Get Unique Names
To get a list of unique names from the Employees
table, you can use the following query:
SELECT DISTINCT Name
FROM Employees;
Output:
Query to Get Unique Combinations of Name and Department
To get a list of unique combinations of names and departments, you can use the following query:
SELECT DISTINCT Name, Department
FROM Employees;
Output:
Name |
Department |
John |
Sales |
Jane |
Marketing |
Alice |
HR |
Bob |
Sales |
In this example, the SELECT DISTINCT
statement ensures that only unique combinations of Name
and Department
are returned.