Where and Having Clause in SQL

The principal distinction between the WHERE and HAVING clause, comes when utilized all together by provision. All things considered, WHERE is used to channel lines before gathering, and HAVING is used to bar records after gathering. This is the main contrast, and if you recollect this, it will assist you with composing better SQL questions. This is likewise one of the significant SQL ideas to comprehend, according to a meeting viewpoint as well as from an everyday utility point of view. I’m certain you have utilised the WHERE provision since it’s one of the most well-known statements in SQL alongside SELECT and used to determine sifting standards or conditions.

You could utilise the WHERE statement without HAVING or GROUP BY, as you have seen commonly. Then again, HAVING must be utilised assuming that gathering has been performed involving the GROUP BY statement in the SQL question.

Another quite important thing about the WHERE and HAVING proviso is that the WHERE statement can’t contain total capacities like COUNT(), SUM(), MAX(), MIN(), and so on yet the HAVING condition might contain total capacities.

Another quite important distinction among WHERE and HAVING proviso is that WHERE is utilised to force sifting model on a SELECT, UPDATE, DELETE proclamation as well as single column work and utilized before bunch by statement yet HAVING is generally utilised after bunch by condition.

When to use “WHERE” and “HAVING” clauses?

However both are used to prohibit lines from the outcome set, you should utilize the WHERE clause to channel lines before gathering and use the HAVING clause to channel lines after gathering. All in all, WHERE can be used to channel on table segments while HAVING can be used to channel on total capacities like count, aggregate, avg, min, and max.

If separating should be possible without total capacity, you should do it on the WHERE statement since it further develops execution since counting and arranging will be done on a much more modest set. Assuming you channel similar lines after gathering, you pointlessly bear the expense of arranging, which isn’t utilised.

Contrast among WHERE and HAVING clause

1. The WHERE proviso is utilised in the determination of lines as per given conditions though the HAVING statement is utilised in segment activities and is applied to accumulated lines or gatherings.
2. If GROUP BY is utilised, it is executed after the WHERE proviso is executed in the question. It implies it chooses the columns before gathering is done or total computations are performed. That’s Why, WHERE proviso is likewise called Pre-channel. Be that as it may, GROUP BY is executed before the execution of the HAVING provision. It implies it chooses the lines after total estimations are performed. That’s Why, HAVING statement is additionally called a Post-channel.
3. We can’t utilise the HAVING proviso without SELECT proclamation though the WHERE condition can be utilised with SELECT, UPDATE, DELETE, and so on
4. WE can utilise total capacities like aggregate, min, max, avg, and so forth with the HAVING statement however they can never be utilized with WHERE provision.
5. HAVING statement is by and large utilized with the GROUP BY. If you utilise the HAVING statement without GROUP BY, likewise it can allude to any segment yet it will not be utilized while playing out the question, not at all like WHERE proviso.
6. Model: The accompanying inquiry has similar outcomes. The WHERE statement utilizes the “age” list yet the having condition will filter the full table rather than straightforwardly taking a gander at the “age” section.

Conclusion

The principal contrast between them is that the WHERE statement is utilised to indicate a condition for sifting records before any groupings are made, while the HAVING proviso is utilised to determine a condition for separating values from a gathering.