SQLite - DISTINCT Keyword

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The SQLite 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 COMPANY table is having the following records:

ID          NAME        AGE         ADDRESS     SALARY
----------  ----------  ----------  ----------  ----------
1           Paul        32          California  20000.0
2           Allen       25          Texas       15000.0
3           Teddy       23          Norway      20000.0
4           Mark        25          Rich-Mond   65000.0
5           David       27          Texas       85000.0
6           Kim         22          South-Hall  45000.0
7           James       24          Houston     10000.0
8           Paul        24          Houston     20000.0
9           James       44          Norway      5000.0
10          James       45          Texas       5000.0

First, let us see how the following SELECT query returns duplicate salary records:

sqlite> SELECT name FROM COMPANY;

This would produce the following result:

NAME
----------
Paul
Allen
Teddy
Mark
David
Kim
James
Paul
James
James

Now, let us use DISTINCT keyword with the above SELECT query and see the result:

sqlite> SELECT DISTINCT name FROM COMPANY;

This would produce the following result, where we do not have any duplicate entry:

NAME
----------
Paul
Allen
Teddy
Mark
David
Kim
James


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