SQL SELECT DISTINCT Statement
Redundancy is the repetition of certain data in a table. With the use of DISTINCT clause data redundancy may be avoided. This clause will eliminate the repetitive appearance of same data. DISTINCT can come only once in a given select statement.
Syntax :
SELECT DISTINCT <column_name> FROM <table_name> WHERE <conditions>;
Parameters :
Name | Description |
---|---|
column_name | Name of the column. |
table_name | Name of the table. |
conditions | It may be a condition, a select query or an expression. |
- SELECT DISTINCT returns only distinct (different) values.
- SELECT DISTINCT eliminates duplicate records from the results.
- DISTINCT can be used with aggregates: COUNT, AVG, MAX, etc.
- DISTINCT operates on a single column. DISTINCT for multiple columns is not supported.