How to find duplicate count among several columns?

Question

Here is a sample table that mimics my scenario:

COL_1   COL_2   COL_3   COL_4   LAST_COL
A       P       X       NY      10
A       P       X       NY      11
A          


        

Answer 1

are having most number of rows

So you want to count, and then ORDER BY the count DESC

SELECT    COL_1, COL_2, COL_3, COL_4, COUNT(*) COUNT_ROWS
FROM      TBL
GROUP BY  COL_1, COL_2, COL_3, COL_4
ORDER BY  COUNT_ROWS DESC