SELECT UNIQUE in SQL

The UNIQUE keyword in a SELECT statement is used to return distinct rows — that is, it eliminates duplicate rows from the result set.

Overview

• SELECT UNIQUE is functionally equivalent to SELECT DISTINCT.

• It is mainly supported in Oracle and some other databases.

• It ensures that the query returns only unique rows.

Syntax:

SELECT UNIQUE column1, column2, ...FROM table_nameWHERE condition;

Example:

Suppose you have a students table with multiple rows having the same city values.

SELECT UNIQUE cityFROM students;

This query will return each city only once, no duplicates.

Equivalent using DISTINCT (more common):

SELECT DISTINCT cityFROM students;

Notes:

• Both UNIQUE and DISTINCT remove duplicate rows.

• DISTINCT is supported by nearly all SQL databases; UNIQUE is less common.

• Use either to get unique values in a column or combination of columns.

If you want examples using multiple columns or complex queries with UNIQUE or DISTINCT, just ask!