Cyber Security · मराठी आवृत्ती
LIKE, IN, BETWEEN आणि NULL
Pattern, choices चा set, range आणि missing values यांसाठी वेगवेगळे operators वापरू.
SELECT name FROM students WHERE name LIKE 'R%'; -- starts with R
SELECT name FROM students WHERE name LIKE '%Bagale'; -- ends with Bagale
SELECT name FROM students WHERE email LIKE '%a%@%'; -- 'a' before @
SELECT name FROM students WHERE name LIKE '_a%'; -- second letter a (_ = one char)
SELECT name, city FROM students WHERE city IN ('Pune', 'Nashik', 'Solapur');
SELECT name, city FROM students WHERE city NOT IN ('Pune');
SELECT name, age FROM students WHERE age BETWEEN 22 AND 25; -- inclusive
SELECT name, joined_on FROM students WHERE joined_on BETWEEN '2026-03-01' AND '2026-03-31';
SELECT name FROM students WHERE email IS NULL; -- not "= NULL"! → Raja
SELECT name FROM students WHERE age IS NOT NULL;
| Wildcard | Meaning | Example |
|---|---|---|
% |
Zero or more characters | 'Pu%' → Pune |
_ |
Exactly one character | 'R_ja' → Raja |
LIKE: % शून्य किंवा अनेक characters; _ नेमका एक character. त्यामुळे R% म्हणजे R ने सुरू, %Bagale म्हणजे Bagale ने शेवट आणि _a% म्हणजे दुसरं अक्षर a. Case sensitivity collation वर अवलंबून असते.
IN: दिलेल्या list मधली value; NOT IN उलट. BETWEEN: दोन्ही endpoints सहित range. Source चं joined_on हे DATE असल्याने March 1–31 example सोपा आहे; DATETIME साठी दिवसाच्या शेवटचा time वेगळा विचारावा लागतो.
NULL: missing/unknown value. = NULL वापरून match होत नाही; IS NULL/IS NOT NULL वापरा. NULL म्हणजे रिकामी string किंवा zero नाही.
Practice
दुसरं अक्षर a असलेली नावं, age 21–24, Nagpur/Kolhapur मधले IN वापरून students आणि email नसलेले students शोधा.