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SELECT DISTINCT column1, column2,
FROM table_name;
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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;
/*
Code language: SQL (Structured Query Language) (sql)
In this statement:
First, the CTE uses the ROW_NUMBER() function to find the duplicate rows
specified by values in the first_name, last_name, and email columns.
Then, the DELETE statement deletes all the duplicate rows but keeps only one
occurrence of each duplicate group.*/
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-- Oracle
DELETE FROM films
WHERE rowid NOT IN (
SELECT min(rowid)
FROM films
GROUP BY title, uk_release_date
);
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DELETE FROM [SampleDB].[dbo].[Employee]
WHERE ID NOT IN
(
SELECT MAX(ID) AS MaxRecordID
FROM [SampleDB].[dbo].[Employee]
GROUP BY [FirstName],
[LastName],
[Country]
);
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SELECT s.siteName, s.siteIP, h.date
FROM sites s INNER JOIN
(select h.*, row_number() over (partition by siteName order by date desc) as seqnum
from history h
) h
ON s.siteName = h.siteName and seqnum = 1
ORDER BY s.siteName, h.date
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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;
Code language: SQL (Structured Query Language) (sql)
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WITH CTE AS(
SELECT [col1]
,[col2]
,[col3]
,
RN = ROW_NUMBER()OVER(PARTITION BY [col1],[col2],[col3] ORDER BY [col1],[col2],[col3])
FROM [dbo].[table1]
)
DELETE FROM CTE WHERE RN > 1