What is the difference between the “HAVING” clause and the “WHERE” clause in SQL?

The Difference Between the 'HAVING' Clause and the 'WHERE' Clause in SQL

When it comes to SQL queries, understanding the distinction between the 'HAVING' clause and the 'WHERE' clause is crucial for efficient data retrieval and manipulation. The focus keyword for this topic is "HAVING clause vs WHERE clause in SQL."

WHERE Clause

The 'WHERE' clause is used to filter records based on a specific condition before any grouping or aggregation takes place. It is applied to individual rows in the result set, allowing you to restrict the rows that meet the specified criteria. For example:

SELECT column1, column2
FROM table_name
WHERE condition;

HAVING Clause

On the other hand, the 'HAVING' clause is used to filter records based on a specific condition after the data has been grouped using the 'GROUP BY' clause. It is applied to grouped rows, allowing you to filter the aggregated results based on specified conditions. For example:

SELECT column1, COUNT(column2)
FROM table_name
GROUP BY column1
HAVING COUNT(column2) > 10;

In summary, while the 'WHERE' clause is used to filter individual rows, the 'HAVING' clause is used to filter aggregated results based on specified conditions after grouping. Understanding when to use each clause is essential for writing efficient and effective SQL queries.