The SELECT DISTINCT statement is used to retrieve unique values from a column in a table. It filters out duplicate values and returns only distinct records.
The basic syntax for the SELECT DISTINCT statement is:
SELECT DISTINCT column1, column2, ...
FROM table_name;
Here, only distinct (unique) values for the specified columns will be returned.
Consider the following Products table:
| ProductID | ProductName | Category | Price |
|---|---|---|---|
| 1 | Laptop | Electronics | $1000 |
| 2 | Mouse | Electronics | $20 |
| 3 | Chair | Furniture | $150 |
| 4 | Laptop | Electronics | $950 |
| 5 | Desk | Furniture | $200 |
To get a list of unique product categories from the Products table, you can use the following SQL query:
SELECT DISTINCT Category
FROM Products;
This query returns the distinct categories in the Products table, like Electronics and Furniture.
You can also select distinct values from multiple columns. For example, to get a list of unique product names and their categories, use the following query:
SELECT DISTINCT ProductName, Category
FROM Products;
This query will return unique combinations of product names and categories.
The following would be the result of the query:
| ProductName | Category |
|---|---|
| Laptop | Electronics |
| Mouse | Electronics |
| Chair | Furniture |
| Desk | Furniture |