How to Find Duplicate values in a Table? SQL GROUP BY and Having Example| Leetcode Solution

To find duplicate values in a table using SQL, you can use the GROUP BY clause along with the HAVING clause. Here's an example: 

Let's say we have a table named "employees" with columns "id" and "name". To find duplicate names in the table, you can use the following query:

SELECT name, COUNT(*) as count
FROM employees
GROUP BY name
HAVING count > 1;Explanation:

The SELECT statement retrieves the "name" column and counts the number of occurrences for each name.
The GROUP BY clause groups the rows based on the "name" column.
The HAVING clause filters the groups and selects only those with a count greater than 1, i.e., the duplicate names.
The result of this query will give you the duplicate names in the "employees" table along with their occurrence count.

As for the Leetcode solution, it would depend on the specific problem you are trying to solve on Leetcode. Different problems may require variations in the query logic or additional conditions. However, the example provided above should give you a good starting point for finding duplicate values in a table using SQL.

Explanation: 

• The SELECT statement retrieves the "name" column and counts the number of occurrences for each name. 
• The GROUP BY clause groups the rows based on the "name" column. 
• The HAVING clause filters the groups and selects only those with a count greater than 1, i.e., the duplicate names. 

The result of this query will give you the duplicate names in the "employees" table along with their occurrence count. 

As for the Leetcode solution, it would depend on the specific problem you are trying to solve on Leetcode. 

Different problems may require variations in the query logic or additional conditions. However, the example provided above should give you a good starting point for finding duplicate values in a table using SQL.