sql delete duplicate rows code example

Example 1: sql count duplicate rows

SELECT _column, COUNT(*) 
FROM _table
GROUP BY _column
HAVING COUNT(*) > 1

Example 2: t-sql get duplicate rows

SELECT [CaseNumber], COUNT(*) AS Occurrences
FROM [CaseCountry]
GROUP BY [CaseNumber]
HAVING (COUNT(*) > 1)

Example 3: sql delete duplicate

-- Oracle
DELETE films
WHERE rowid NOT IN (
    SELECT min(rowid)
    FROM films
    GROUP BY title, uk_release_date
);

Example 4: sql server delete records that have a single duplicate column

WITH cte AS (
    SELECT 
        contact_id, 
        first_name, 
        last_name, 
        email, 
        ROW_NUMBER() OVER (
            PARTITION BY 
                first_name, 
                last_name, 
                email
            ORDER BY 
                first_name, 
                last_name, 
                email
        ) row_num
     FROM 
        sales.contacts
)
DELETE FROM cte
WHERE row_num > 1;

Example 5: how to query without duplicate rows in sql

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

Example 6: 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;