Uniq entry from a table in sql

The SQL DISTINCT clause is used together with the SQL SELECT keyword, to return a dataset with unique entries for certain database table column.

SELECT DISTINCT LastName FROM Customers 

SELECT DISTINCT(id_email), email_name, email FROM emails LEFT JOIN emails_lists ON emails.id_email = emails_lists.fk_email WHERE email_valid = 1 AND fk_list IN ($fk_list)

Here's a handy query for finding duplicates in a table. Suppose you want to find all email addresses in a table that exist more than once:
SELECT email, 
 COUNT(email) AS NumOccurrences
FROM users
GROUP BY email
HAVING ( COUNT(email) > 1 )
You could also use this technique to find rows that occur exactly once:
SELECT email
FROM users
GROUP BY email
HAVING ( COUNT(email) = 1 )

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