SQL Distinct
Once a table starts getting a lot of data in it, some columns will contain duplicate values. For example, many Individuals share first names and surnames. Most of the time this isn't a problem. But sometimes you will want to find out how many unique values there are in a table. To do this you can use the DISTINCT keyword.
SQL statement
SELECT DISTINCT(FirstName) FROM Individual
Source Table
| IndividualId | FirstName | LastName | UserName |
|---|---|---|---|
| 1 | Fred | Flinstone | freddo |
| 2 | Homer | Simpson | homey |
| 3 | Homer | Brown | notsofamous |
| 4 | Ozzy | Ozzbourne | sabbath |
| 5 | Homer | Gain | noplacelike |
Result
Using the DISTINCT keyword, all customers with a name of "Homer" are counted as one.
| FirstName |
|---|
| Fred |
| Homer |
| Ozzy |