What is the method for counting duplicate data in MySQL?

6 months ago

1 minute

To calculate the number of duplicate data in a MySQL table, you can use the following SQL query statement:

SELECT column_name, COUNT(column_name) AS count
FROM table_name
GROUP BY column_name
HAVING COUNT(column_name) > 1;

In this case, column_name refers to the column where duplicate data needs to be calculated, and table_name is the name of the table to be queried. This query statement will group the specified column and calculate the number of duplicate data entries within each group. Finally, only the groups with more than one duplicate entry will be returned.