The SQL DISTINCT clause is used together with the SQL SELECT statement, to return a dataset with unique entries for certain database table column.
In a table, some of the columns may contain duplicate values. This is not a problem but sometimes you will want to list only the different (distinct) values in a table. The SQL DISTINCT clause can be used to return only distinct (different) values.
SELECT DISTINCT column_name(s) FROM table_name
We will use our Customers database table to illustrate the usage of the SQL DISTINCT clause.
| LName | FName | |
|---|---|---|
| John | Smith | John.Smith@yahoo.com |
| Steven | Goldfish | goldfish@gmail.com |
| Paula | Kari | pb@plasa.com |
| James | Smith | jim@yahoo.co.uk |
For example if we want to select all distinct FName from our Customers table, we will use the following the SQL DISTINCT clause:
SELECT DISTINCT FName FROM Customers
The result of the SQL DISTINCT clause expression above will look like this:
| FName |
|---|
| Smith |
| Goldfish |
| Kari |
