SQL server multi-field deduplication keeps a record

1. Purpose:

Delete duplicate data in some fields and keep one of the record data

2. Effect picture:

Before processing:

After processing:

3，SQL

delete FROM Atable WHERE EXISTS (
	SELECT id FROM( SELECT name, code FROM Atable GROUP BY name, code HAVING COUNT ( * ) > 1 ) tableabc 
	WHERE Atable.name= tableabc.name AND Atable.code= tableabc.code ) 
AND id NOT IN (
	    SELECT MIN(id) FROM Atable GROUP BY name,code HAVINGCOUNT ( * ) > 1)

Explanation : Extract the duplicate data of the Atable table, as a temporary table tableabc, join tableabc and Atable to extract the duplicated part, and only keep the record data with the smallest id in the duplicate data.