|4. WHERE — Data Filter करणे
Chapter 4SQL Tutorial~1 min read

WHERE — Data Filter करणे

WHERE, AND, OR, IN, BETWEEN, LIKE

WHERE clause conditions वापरून specific rows filter करतो. Comparison operators, logical operators, IN, BETWEEN, LIKE — सगळे WHERE मध्ये वापरता येतात.

Basic WHERE conditions

sql
-- Comparison operators
SELECT * FROM students WHERE marks > 80;
SELECT * FROM students WHERE city = 'Pune';
SELECT * FROM students WHERE marks != 85;
SELECT * FROM students WHERE marks >= 40 AND marks <= 80;

-- AND, OR, NOT
SELECT * FROM students
WHERE city = 'Pune' AND marks > 80;

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

SELECT * FROM students
WHERE NOT city = 'Nagpur';

IN, BETWEEN, LIKE

IN, BETWEEN, LIKE operators

sql
-- IN — multiple values check
SELECT * FROM students
WHERE city IN ('Pune', 'Mumbai', 'Nagpur');

-- NOT IN — exclude values
SELECT * FROM students
WHERE city NOT IN ('Nashik');

-- BETWEEN — range check (inclusive!)
SELECT * FROM students
WHERE marks BETWEEN 60 AND 90;
-- marks >= 60 AND marks <= 90 सारखेच

-- Date range
SELECT * FROM students
WHERE dob BETWEEN '2000-01-01' AND '2005-12-31';

-- LIKE — pattern matching
-- % = कितीही characters, _ = exactly 1 character
SELECT * FROM students WHERE name LIKE 'R%';      -- R ने सुरू
SELECT * FROM students WHERE name LIKE '%a';       -- a ने संपतो
SELECT * FROM students WHERE name LIKE '%Patil%'; -- Patil असलेले
SELECT * FROM students WHERE name LIKE 'R_h_l';   -- Rahul pattern
📌

LIKE pattern मध्ये % म्हणजे कोणतेही characters (0 किंवा जास्त) आणि _ म्हणजे exactly एक character. 'R%' = R ने सुरू होणारे सगळे. '%@gmail.com' = gmail addresses सगळे.

Key Points — लक्षात ठेवा

  • =, !=, <, >, <=, >= — comparison operators
  • AND, OR, NOT — logical operators
  • IN (val1, val2) — list of values
  • BETWEEN a AND b — range (inclusive)
  • LIKE 'pattern' — % कोणतेही, _ एक character
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