SQL WHERE

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The WHERE clause in SQL is used to filter records from a table. It specifies a condition, and only the rows that satisfy that condition are returned or affected.

Basic Syntax 

SELECT column1, column2
FROM table_name
WHERE condition;

WHERE with SELECT: Retrieve students from Delhi. 

SELECT * 
FROM students
WHERE city = 'Delhi';

WHERE with Comparison Operators 

SELECT * 
FROM students
WHERE marks > 80;

Returns students who scored more than 80

WHERE with AND / OR 

AND (both conditions must be true)

SELECT * 
FROM students
WHERE city = 'Delhi' AND marks > 80;


OR (any condition true)

SELECT * 
FROM students
WHERE city = 'Delhi' OR city = 'Pune';

WHERE with BETWEEN: Used for a range.

SELECT * 
FROM students
WHERE marks BETWEEN 70 AND 90;

WHERE with IN: Check multiple values. 

SELECT * 
FROM students
WHERE city IN ('Delhi', 'Mumbai');

WHERE with LIKE: Used for pattern matching.

SELECT * 
FROM students
WHERE name LIKE 'R%';

Meaning: names starting with R.

Update 

UPDATE students
SET marks = 95
WHERE id = 1;


Summary
      • WHERE filters rows based on conditions.
      • Used with commands like SELECT, UPDATE, DELETE.

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