The SQL SELECT DISTINCT Statement
The SQL SELECT DISTINCT Statement
The SQL SELECT DISTINCT statement is used to retrieve unique values from a specified column or columns in a table. It is similar to the SELECT statement, but it only returns distinct or unique values, removing duplicates. Here is the basic syntax of a SELECT DISTINCT statement:
SELECT DISTINCT column1, column2, ...
FROM table_name
WHERE condition;
- The SELECT DISTINCT clause specifies the columns to retrieve distinct or unique values from in the specified table(s).
- The FROM clause specifies the table(s) to retrieve data from.
- The WHERE clause is optional and is used to filter data based on a specified condition. If no WHERE clause is included, all rows in the specified table(s) will be retrieved.
Here is an example of a basic SELECT DISTINCT statement:
SELECT DISTINCT country
FROM customers;
This statement retrieves only the unique values in the country column from the customers table, removing any duplicates.
You can also use multiple columns in the SELECT DISTINCT clause to retrieve unique combinations of values. For example:
SELECT DISTINCT first_name, last_name
FROM customers;
This statement retrieves only the unique combinations of first and last names from the customers table, removing any duplicates.
Overall, the SELECT DISTINCT statement is useful when you want to retrieve unique or distinct values from a specified column or columns in a table