MarquinSmith

-- SQL query to identify and display rows of a table that are duplicates

WITH duplicate_count AS (
    SELECT
        column_a,
        column_b,
        column_c,
        COUNT(*) AS records
    FROM table_1
    GROUP BY
        column_a,
        column_b,
        column_c
)

-- count rows where duplicates have been found
SELECT 
	COUNT(*) AS num_duplicate_records
FROM duplicate_count
WHERE 
	records > 1;

-- show rows that are duplicated
-- rank in order of rows most duplicated first
SELECT
	*
FROM duplicate_count
WHERE 
	records >1
ORDER BY
	records DESC