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DISTINCT
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SELECT DISTINCT <column> FROM <table>
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DISTINCT qualifier is used to
remove duplicate rows from SELECT command.
Table: Orders
| OrderID |
Customer |
Employee |
Order Date |
ShippedVia |
Freight |
ShipCountry |
| 10248 |
Wilman Kala |
Buchanan, Steven |
04-07-1996 |
Federal Shipping |
32.38 |
France |
| 10249 |
Hanari Carnes |
Peacock, Margaret |
08-07-1996 |
United Package |
65.83 |
Brazil |
| 10250 |
Hanari Carnes |
Leverling, Janet |
08-Jul-1996 |
United Package |
58.17 |
Brazil |
| 10251 |
Chop-suey Chinese |
Buchanan, Steven |
11-Jul-1996 |
United Package |
22.98 |
Switzerland |
| 10252 |
Richter Supermarkt |
Dodsworth, Anne |
12-Jul-1996 |
Federal Express |
148.33 |
Switzerland |
The following SQL statement will return ShipCountry for all records
in Orders table as shown in Resultset1.
SELECT
ShipCountry FROM Orders
Resultset1
| ShipCountry |
| France |
| Brazil |
| Brazil |
| Switzerland |
| Switzerland |
As you can see, Resultset1 contains duplicate rows. Brazil and
Switzerland appear twice in the resultset1.
The following SQL statement will remove the duplicate rows with
DISTINCT qualifier.
SELECT
DISTINCT
ShipCountry FROM Orders
Resultset2
| ShipCountry |
| France |
| Brazil |
| Switzerland |
Brazil and Switzerland only appear once in Resultset2.
.
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