Finding duplicate values in MySQL

Question

I have a table with a varchar column, and I would like to find all the records that have duplicate values in this column. What is the best query I can use to find the duplic

Answer 1

Do a SELECT with a GROUP BY clause. Let's say name is the column you want to find duplicates in:

SELECT name, COUNT(*) c FROM table GROUP BY name HAVING c > 1;

This will return a result with the name value in the first column, and a count of how many times that value appears in the second.

Answer 2

To find how many records are duplicates in name column in Employee, the query below is helpful;

Select name from employee group by name having count(*)>1;

Answer 3

SELECT varchar_col
FROM table
GROUP BY varchar_col
HAVING COUNT(*) > 1;

Answer 4

I improved from this:

SELECT 
    col, 
    COUNT(col)
FROM
    table_name
GROUP BY col
HAVING COUNT(col) > 1; 

Answer 5

Try using this query:

SELECT name, COUNT(*) value_count FROM company_master GROUP BY name HAVING value_count > 1;

Answer 6

SELECT t.*,(select count(*) from city as tt
  where tt.name=t.name) as count
  FROM `city` as t
  where (
     select count(*) from city as tt
     where tt.name=t.name
  ) > 1 order by count desc

Replace city with your Table. Replace name with your field name