Open In App
Related Articles

Having vs Where Clause in SQL

Improve Article
Save Article
Like Article

The difference between the having and where clause in SQL is that the where clause cannot be used with aggregates, but the having clause can.

The where clause works on row’s data, not on aggregated data.  Let us consider below table ‘Marks’.

Student       Course      Score

a                c1             40

a                c2             50

b                c3             60

d                c1             70

e                c2             80

Consider the query

SELECT Student, Score FROM Marks WHERE Score >=40

This would select data row by row basis.

The having clause works on aggregated data.

For example,  output of below query

SELECT Student, SUM(score) AS total FROM Marks GROUP BY Student

Student     Total

a              90

b               60

d               70

e               80

When we apply having in above query, we get

SELECT Student, SUM(score) AS total FROM Marks GROUP BY Student

HAVING total > 70

Student     Total

a              90

e               80


Note:  It is not a predefined rule but  in a good number of the SQL queries, we use WHERE prior to GROUP BY and HAVING after GROUP BY. The Where clause acts as a pre filter where as Having as a post filter.

Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above

Unlock the Power of Placement Preparation!
Feeling lost in OS, DBMS, CN, SQL, and DSA chaos? Our Complete Interview Preparation Course is the ultimate guide to conquer placements. Trusted by over 100,000+ geeks, this course is your roadmap to interview triumph.
Ready to dive in? Explore our Free Demo Content and join our Complete Interview Preparation course.

Last Updated : 20 Aug, 2019
Like Article
Save Article
Similar Reads