Difference between From and Where Clause in SQL

1. FROM Clause:
It is used to select the dataset which will be manipulated using Select, Update or Delete command.It is used in conjunction with SQL statements to manipulate dataset from source table.We can use subqueries in FROM clause to retrieve dataset from table.

Syntax of FROM clause:

SELECT * 
FROM TABLE_NAME; 

2. WHERE Clause:
It is used to apply any condition on selected dataset or source data.Source data can be a single table or can be a result of joining multiple tables.It returns those instances of dataset which satisfies the condition mentioned in WHERE clause.Conditions can be applied using various comparison or logical operators like –
AND, OR, IN, NOT IN, BETWEEN, equals to, not equals to etc.

Syntax of WHERE clause:

SELECT * FROM TABLE_NAME
WHERE (CONDITIONS); 

Example:
Consider a table name STUDENT



S_NO. s_NAME S_AGE S_SECTION
1 Yash 20 A
2 Vishwash 21 A
3 Vishesh 19 B
4 Shivam 23 A
5 Vasu 21 B
6 Shrey 20 C

Problem:
We have to select those instances of table STUDENT where age is less than 22 and section is A.

Query:

SELECT * 
FROM STUDENT 
WHERE S_AGE<22 AND S_SECTION='A'; 

OUTPUT:
Here FROM clause chooses the table on which the WHERE clause should be applied and WHERE clause checks the two condition to find which instances of the dataset are satisfying them.

S_NO. s_NAME S_AGE S_SECTION
1 Yash 20 A
2 Vishwash 21 A

Differences between FROM Clause and WHERE Clause :

S_NO. FROM Clause WHERE Clause
1. It is used to select the dataset on which manipulation has to be done. It is used for checking some conditions to filter result
2. We provide some dataset into the FROM clause as a input. In WHERE clause we give some condition as input.
3. FROM clause selects dataset to provide it to WHERE clause for applying conditions given in query. WHERE clause act as selector which filters required instances from dataset provide by FROM clause.
4. FROM clause is mandatory because if there is no dataset, no manipulation can be performed. WHERE is optional, we use it only in case of condition checking.

Attention reader! Don’t stop learning now. Get hold of all the important DSA concepts with the DSA Self Paced Course at a student-friendly price and become industry ready.

My Personal Notes arrow_drop_up

Check out this Author's contributed articles.

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.


Article Tags :
Practice Tags :


Be the First to upvote.


Please write to us at contribute@geeksforgeeks.org to report any issue with the above content.