no duplicates in sql code example

Example 1: select count of distinct values sql

SELECT COUNT (DISTINCT column-name)  FROM table-name

Example 2: how to query without duplicate rows in sql

SELECT DISTINCT col1,col2... FROM table_name where Condition;

Example 3: how to remove duplicate in sql

Distinct: helps to remove all the duplicate
records when retrieving the records from a table.

SELECT DISTINCT FIRST_NAME FROM VISITORS;

Example 4: sql server select rows by distinct column

SELECT a.*
FROM emails a
INNER JOIN 
  (SELECT email,
    MIN(id) as id
  FROM emails 
  GROUP BY email 
) AS b
  ON a.email = b.email 
  AND a.id = b.id;

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