How To Count Duplicated Values in a Column


How To Count Duplicated Values in a Column? - MySQL FAQs - SQL SELECT Query Statements with GROUP BY



If you have a column with duplicated values, and you want to know what are those duplicated values are and how many duplicates are there for each of those values, you can use the GROUP BY ... HAVING clause as shown in the following example. It returns how many duplicated first names in the fyi_team table:

mysql> SELECT first_name, COUNT(*) FROM fyi_team 
   GROUP BY first_name HAVING COUNT(*) > 1;
| first_name | COUNT(*) |
| John       |        6 |
1 row in set (0.01 sec)

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