डाटाबेस र DBMS – Database & DBMS MCQ
डाटाबेस र DBMS – कम्प्युटर र IT
Database & DBMS · Computer & IT (Technical) · ५६३ प्रश्न
५६३ प्रश्न उपलब्ध। मोड छान्नुहोस्:
डाटाबेस र DBMS: प्रश्न र उत्तर
सही लागेको विकल्पमा थिच्नुहोस्। सही भए हरियो, गलत भए रातो देखिन्छ; ३ सेकेन्डपछि सही उत्तर र व्याख्या देखिन्छ।
सही: ० / ०
-
The SQL operator EXISTS returns true when:
सही उत्तर: ग) The subquery returns at least one row
EXISTS only checks whether the subquery produces any row; the values themselves are not compared.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
In SQL, the condition salary > ALL (SELECT salary FROM emp WHERE dept = 'D1') is true when salary is:
सही उत्तर: ख) Greater than the highest salary in department D1
> ALL requires the value to exceed every value returned by the subquery, i.e. its maximum; > ANY needs only to exceed the minimum.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
COMMIT, ROLLBACK and SAVEPOINT belong to which category of SQL commands?
सही उत्तर: क) TCL (Transaction Control Language)
TCL commands manage transactions: COMMIT makes changes permanent, ROLLBACK undoes them and SAVEPOINT marks a point to roll back to.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
In which logical order are the clauses of an SQL SELECT statement processed?
सही उत्तर: क) FROM, WHERE, GROUP BY, HAVING, SELECT, ORDER BY
Rows are taken FROM tables, filtered by WHERE, grouped, groups filtered by HAVING, columns produced by SELECT, and finally sorted by ORDER BY.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
In SQL, the condition WHERE commission = NULL:
सही उत्तर: घ) Never evaluates to true, so no rows are returned
Any comparison with NULL using = gives UNKNOWN, which is not true; IS NULL must be used instead.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
Which names are matched by the SQL condition WHERE name LIKE '_a%'?
सही उत्तर: ग) Names whose second letter is 'a'
The underscore matches exactly one character and % matches any sequence, so '_a%' means any first character followed by 'a'.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
Which SQL operator tests whether a value matches any value in a given list, such as WHERE city ___ ('Pokhara', 'Butwal')?
सही उत्तर: ग) IN
IN checks membership in a list of values or a subquery result.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
Which SQL clause sorts the result of a query, for example from highest to lowest salary?
सही उत्तर: घ) ORDER BY salary DESC
ORDER BY sorts the output; ASC (the default) gives ascending order and DESC gives descending order.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
Column dept contains the values D1, D2, D1, NULL and D3. What does SELECT COUNT(DISTINCT dept) return?
सही उत्तर: ख) 3
COUNT(DISTINCT column) counts different non-NULL values: D1, D2 and D3.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
Table Emp has 5 rows with dept_id values 10, 20, 20, 30 and NULL. Table Dept has unique dept_id values 10, 20 and 40. How many rows does Emp INNER JOIN Dept ON Emp.dept_id = Dept.dept_id return?
सही उत्तर: ख) 3
Only employees whose dept_id matches a Dept row join: 10 (one row) and 20 (two rows), giving 3; 30 and NULL have no match.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
यी अभ्यास प्रश्न हुन्, आधिकारिक प्रश्न होइनन्। पाठ्यक्रम, विज्ञापन र नतिजाका लागि सम्बन्धित निकायको आधिकारिक वेबसाइट हेर्नुहोस्। उत्तरमा गल्ती भेटे प्रश्नमुनिको "टिप्पणी / गल्ती रिपोर्ट" मा लेख्नुहोस्।
नमस्ते! पाठ्यक्रम, सामान्य ज्ञान, भाषा परीक्षा वा कुनै प्रश्नको उत्तर बुझ्न सोध्नुहोस्।
AI ले गल्ती गर्न सक्छ। महत्वपूर्ण कुरा आधिकारिक स्रोतमा जाँच्नुहोस्।