SQL Distinct
Keyword
The
SQL DISTINCT keyword is used in conjunction with SELECT statement to eliminate
all the duplicate records and fetching only unique records.
There
may be a situation when you have multiple duplicate records in a table. While
fetching such records, it makes more sense to fetch only unique records instead
of fetching duplicate records.
Syntax:
The
basic syntax of DISTINCT keyword to eliminate duplicate records is as follows:
SELECT
DISTINCT column1, column2,.....columnN
FROM
table_name
WHERE
[condition]
Example:
Consider
the CUSTOMERS table having the following records with some repetition:
+----+-------------+------+-----------------+---------------+
|
ID | NAME | AGE
| ADDRESS | SALARY |
+----+-------------+------+-----------------+---------------+
|
1 | Ramesh | 32
| Ahmedabad | 2000.00 |
|
2 | Ramesh | 25
| Delhi |
1500.00 |
|
3 | kaushik | 23
| Kota |
2000.00 |
|
4 | Chaitali | 25
| Mumbai | 6500.00 |
|
5 | Chaitali | 27
| Bhopal | 8500.00 |
|
6 | Komal | 22
| MP | 4500.00
|
|
7 | Muffy | 24
| Indore |
10000.00 |
+----+-------------+------+-----------------+---------------+
Let us
use DISTINCT keyword with the above
SELECT query and see the result:
SQL>
SELECT DISTINCT SALARY FROM CUSTOMERS
ORDER
BY SALARY;
This
would produce the following result where
we do not have any duplicate entry:
+---------------+
|
SALARY |
+---------------+
|
1500.00 |
|
2000.00 |
|
4500.00 |
|
6500.00 |
|
8500.00 |
|
10000.00 |
+---------------+
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