Thursday, September 21, 2023

How can you retrieve unique values from a column in SQL?

 To retrieve unique values from a column in SQL, you can use the DISTINCT keyword in conjunction with the SELECT statement.

Here's the basic syntax for retrieving unique values from a column:

FROM table_name;

Here's a breakdown of how to use this syntax:

  • SELECT DISTINCT: Start your SQL query with the SELECT DISTINCT clause. This instructs the database to return only unique values from the specified column.
  • column_name: Replace column_name with the name of the column from which you want to retrieve unique values.
  • FROM table_name: Specify the name of the table that contains the column you're interested in. This indicates the source of the data.

For example, if you have a table named "Employees" and you want to retrieve the unique values of the "Department" column, your SQL query would look like this

FROM Employees;

Executing this query would return a list of unique department names from the "Department" column of the "Employees" table.

It's important to note that DISTINCT operates on all selected columns, so if you select multiple columns, the DISTINCT keyword will ensure that the combination of values in those columns is unique. If you only want to retrieve unique values from one specific column, include only that column in your SELECT statement.

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