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

SELECT COL_1, COL_2, COL_3, COL_4, COUNT(*)
FROM MyTable
GROUP BY COL_1, COL_2, COL_3, COL_4

If you ever want to weed out rows that don't have a duplicate:

SELECT COL_1, COL_2, COL_3, COL_4, COUNT(*)
FROM MyTable
GROUP BY COL_1, COL_2, COL_3, COL_4
HAVING COUNT(*) > 1

Answer 2

If I am understanding correctly all you need is something like:

SELECT COL_1,COL_2,COL_3,COL_4, COUNT(*) AS TOTAL
FROM table
GROUP BY COL_1,COL_2,COL_3,COL_4

Answer 3

The GROUP BY is what you want here. For example:

SELECT COL_1, COL_2, COL_3, COL_4, COUNT(*)
FROM my_table
GROUP BY COL_1, COL_2, COL_3, COL_4

Answer 4

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