What Does SELECT DISTINCT * Do in SQL? Explained

Learn how SELECT DISTINCT * in SQL returns unique rows by removing duplicates from tables for cleaner data retrieval.

80 views

SELECT distinct * in SQL returns unique rows from a specified table. It removes duplicate records, ensuring that each row is distinct based on the columns selected. This is useful for retrieving a set of unique records from a dataset where duplicates might exist.

FAQs & Answers

  1. What is the purpose of SELECT DISTINCT in SQL? SELECT DISTINCT is used in SQL to return only unique rows from a table by eliminating duplicate records based on the selected columns.
  2. How is SELECT DISTINCT * different from SELECT * in SQL? SELECT * returns all rows including duplicates, while SELECT DISTINCT * returns only unique rows by removing duplicates from the result set.
  3. Can SELECT DISTINCT improve SQL query performance? Using SELECT DISTINCT can sometimes slow down a query because it requires additional processing to filter duplicates, but it ensures clean and unique data results.

Watch More

For a deeper understanding of SQL querying techniques, consider exploring related content on SQL WHERE clauses, GROUP BY statements, and optimizing SQL queries for better performance.

  1. Which SQL Command Removes Duplicate Records? How to Use DISTINCT Learn how to remove duplicate records in SQL using the DISTINCT keyword with examples for clean query results.
  2. How to Remove Duplicates from SQL Result Sets Using the DISTINCT Command Learn how to remove duplicates from SQL query results using the DISTINCT command to retrieve unique values efficiently.
  3. Does Distinct Remove Duplicates in Programming? Learn how the distinct function removes duplicate values to ensure unique entries in programming datasets.
  4. Which SQL Operator Removes Duplicates from Query Results? Learn how the DISTINCT SQL operator removes duplicate rows from query results for cleaner data analysis.
  5. How to Retrieve Distinct Records Without Using DISTINCT Keyword in SQL? Learn how to get distinct records from a table using GROUP BY instead of DISTINCT in SQL queries for efficient data retrieval.
  6. Is Using DISTINCT Bad in SQL? Pros, Cons, and Best Practices Learn when using DISTINCT in SQL is beneficial and when it impacts performance. Discover best practices for managing duplicates effectively.
  7. Why Is It Important to Remove Duplicates from Your Data and Playlists? Learn why removing duplicates improves performance, saves storage, and enhances user experience by maintaining data integrity.
  8. How to Use the fdupes Command to Delete Duplicate Files in Unix Learn how to use the fdupes command with the -d option to safely find and delete duplicate files in Unix-like systems.
  9. Does Rekordbox Duplicate Tracks? How to Manage Track Duplicates Effectively Learn if Rekordbox duplicates tracks and how to use its duplicate detection feature to keep your music library organized and efficient.