Using SQL Distinct to Exclude Duplicates

Syntax of SQL SELECT DISTINCT

SELECT DISTINCT column1, column2, ...
FROM table_name;

Examples using a demo database

The Developers table

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• High-quality courses (even the free ones)
• Variety of features

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• Suitable for enterprises
• Paid certificates of completion

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Pros

• Professional service
• Flexible timetables
• A variety of features to choose from

Main Features

• Professional certificates of completion
• University-level courses
• Multiple Online degree programs

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Pros

• Great user experience
• Offers quality content
• Very transparent with their pricing

Main Features

• Free certificates of completion
• Focused on data science skills
• Flexible learning timetable

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Selecting all values from one column

SELECT City FROM Developers;

Selecting only distinct values from one column

SELECT DISTINCT City FROM Developers;

Counting distinct values

SELECT COUNT(DISTINCT City) FROM Developers;

Note: this example will not work in Microsoft Edge and Firefox, as they use Microsoft Access which doesn't support COUNT(DISTINCT column_name).

In MS Access

SELECT Count(*) AS DistinctCities
FROM (SELECT DISTINCT City FROM Developers);