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SET ROWCOUNT 1
DELETE [dbo].[table] where .
SET ROWCOUNT 0
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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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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;
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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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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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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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# Step 1: Copy distinct values to temporary table
CREATE TEMPORARY TABLE tmp_user (
SELECT id, name
FROM user
GROUP BY name
);
# Step 2: Remove all rows from original table
DELETE FROM user;
# Step 3: Remove all rows from original table
INSERT INTO user (SELECT * FROM tmp_user);
# Step 4: Remove temporary table
DROP TABLE tmp_user;