Show Unique Data in SQL | Part 7 #sqlserver #coding #dataqueries
In SQL Server, the DISTINCT keyword is used to retrieve unique values from a column or combination of columns in a result set. It eliminates duplicate rows from the query result and only returns distinct values.
Note:- Keep in mind a few things when using DISTINCT
It operates on all selected columns: When you use DISTINCT, it considers all the selected columns as a combination for determining uniqueness. If you want distinct values based on a specific column, you can specify only that column in the SELECT statement.
Ordering: The order of rows in the result set is not guaranteed to be in any specific order. If you need the results to be sorted, you should use an ORDER BY clause.
Performance: While DISTINCT can be useful, it can also impact performance, especially on large datasets. The database engine needs to perform additional work to identify and eliminate duplicate rows.
GROUP BY alternative: In some cases, using GROUP BY might provide more control over aggregations and calculations on top of distinct values. It's worth exploring both options depending on your query requirements.
Remember that using DISTINCT can be resource-intensive, so it's a good practice to only use it when necessary. If you're looking to eliminate duplicates based on specific columns and you don't need other columns in your result set, consider using the GROUP BY clause instead.
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