A SQL query automatically eliminates duplicates (True / False) ? * code example
Example 1: how to query without duplicate rows in sql
SELECT DISTINCT col1,col2... FROM table_name where Condition;
Example 2: sql query to delete duplicate records
SELECT E.ID,
E.firstname,
E.lastname,
E.country,
T.rank
FROM [SampleDB].[dbo].[Employee] E
INNER JOIN
(
SELECT *,
RANK() OVER(PARTITION BY firstname,
lastname,
country
ORDER BY id) rank
FROM [SampleDB].[dbo].[Employee]
) T ON E.ID = t.ID;
DELETE E
FROM [SampleDB].[dbo].[Employee] E
INNER JOIN
(
SELECT *,
RANK() OVER(PARTITION BY firstname,
lastname,
country
ORDER BY id) rank
FROM [SampleDB].[dbo].[Employee]
) T ON E.ID = t.ID
WHERE rank > 1;