find duplicate keys in mysql
snippet in sql

find duplicates mysql column

user6054

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

find duplicate keys in mysql

user7524

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

select where duplicate mysql

user8247

SELECT 
    col1, COUNT(col1),
    col2, COUNT(col2)
FROM
    table_name
GROUP BY 
    col1, 
    col2
HAVING 
       (COUNT(col1) > 1) AND 
       (COUNT(col2) > 1);