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SQL Quiz (200 Questions)
← All topics
SQL Quiz (200 Questions)
199 exercises
·
10 free
01
What Does SQL Stand For?
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02
Which Part Of SQL Is Primarily Used To Retrieve Data?
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03
SQL Is Programming Language For Storing And Processing Information In?
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04
Which Keyword Begins A Query That Retrieves Data From A Table?
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05
SQL Is Considered What Type Of Language?
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06
Which Of The Following Is A Common Relational Database System?
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07
Which Keyword Removes Duplicates In A SELECT Statement?
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08
Which Statement Changes Data In A Database?
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09
n SQL, Which Symbol Is Commonly Used As A Wildcard In Strings?
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10
Which Command Is Used To Remove Rows From A Table?
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11
Which Clause Specifies The Source Table(S) In A Query?
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12
Which Keyword Selects All Columns From A Table?
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13
To Select A Literal String “Hello”, You Can Write:
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14
To Rename A Column In The Result Set, Use:
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15
If You Omit FROM, Selecting From Where Is Possible In Standard SQL?
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To Choose Columns “Name” And “Age” From Table “Persons”:
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A SELECT Statement Without A WHERE Clause Returns:
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18
To Avoid Specifying A Table Alias, You Can:
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19
Which Of These Is A Valid SELECT Syntax?
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Using SELECT Without Specifying Columns Returns:
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The WHERE Clause Is Used To:
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To Select Rows Where Age > 18:
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To Match Rows Where Name Starts With ‘A’:
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To Select Rows Where City Is Either ‘Paris’ Or ‘London’:
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The WHERE Clause Is Placed:
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To Find Rows Where Salary Is NOT 5000:
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27
Which Operator Checks For NULL Values?
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To Exclude Rows With Age = 30:
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To Use A Pattern To Filter Rows Containing ‘Abc’ Anywhere In Name:
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30
To Filter Rows Where Price Is Between 10 And 20 Inclusive:
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31
Which Function Returns The Number Of Rows?
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SUM() Function Is Used To:
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MIN() Function Returns:
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MAX() Function Returns:
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35
AVG() Function Returns:
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36
COUNT(*) Differs From COUNT(Column) By:
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To Get Total Sales From ‘Orders’ Table With ‘Amount’ Column:
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38
To Find The Lowest Salary In Employees Table:
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39
To Count Rows Ignoring NULL In Column ‘Age’:
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40
Which Function Can Remove Duplicates When Counting Distinct Values?
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41
GROUP BY Is Used To:
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GROUP BY Must Be Used With:
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HAVING Clause Filters Rows After:
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To Find Total Sales Per Department:
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HAVING Is Used To Filter Groups, For Example Groups With SUM(Sales)>1000:
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46
If A SELECT Uses GROUP BY, Columns Not Aggregated Must Be:
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47
Average Salary By Job_title But Only Show Groups With Avg>5000:
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48
Without GROUP BY, HAVING Acts Like WHERE, But Standard SQL Requires:
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49
Count Employees Per Department And Only Show Departments With Count>10:
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50
You Cannot Use HAVING Without What?
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51
ORDER BY Is Used To:
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By Default ORDER BY Sorts In:
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To Sort By Name Ascending And Age Descending:
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ORDER BY Must Come:
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To Sort By A Column Not In SELECT, Generally:
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To Sort By Multiple Columns, Separate By:
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To Get Alphabetical Order On ‘Name’:
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To Reverse The Sorting Order:
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If No ORDER BY Specified, Order Of Rows Is:
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ORDER BY Can Sort By Column Position Using:
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INNER JOIN Returns:
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LEFT JOIN Returns:
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RIGHT JOIN Returns:
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FULL OUTER JOIN Returns:
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To Join ‘Orders’ And ‘Customers’ Where Orders.cust_id=Customers.id:
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INNER JOIN Is Also Called:
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To Get All Customers Even If They Have No Orders:
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CROSS JOIN Returns:
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To Filter Joined Results, Use Conditions In:
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70
If You Want All Rows From Both Tables With No Match Replaced By NULLs:
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71
A Subquery Is:
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Subqueries Are Often Used In:
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A Scalar Subquery Returns:
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74
To Find Rows With Value Greater Than The Average, Use:
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A Derived Table Is A Subquery Used:
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A Subquery Returning Multiple Values Can Be Used With:
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Correlated Subqueries:
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To Use A Subquery As A Column List:
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Subqueries Can Appear In:
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A Derived Table Must Have:
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UNION Combines:
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UNION Requires:
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UNION By Default Removes Duplicates. To Keep Duplicates Use:
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INTERSECT Returns:
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EXCEPT Returns:
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Set Operations Typically Require:
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UNION ALL Vs UNION Differs By:
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INTERSECT And EXCEPT Might Not Be Supported By All SQL Dialects. A Common Replacement For INTERSECT Is:
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Set Operators Combine Results Of Multiple SELECTs. The Correct Syntax Usually Is:
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EXCEPT Is Sometimes Known As:
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CREATE TABLE Is Used To:
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B. Removes table structure and data
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ALTER TABLE Is Used To:
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To Remove A Column From A Table:
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CREATE TABLE Syntax Generally Includes:
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To Rename A Table:
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To Add A New Column:
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DDL Statements Like CREATE, DROP, ALTER Usually:
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To Completely Remove A Table And Its Data:
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To Remove All Rows But Keep Table Structure:
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INSERT Is Used To:
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UPDATE Changes:
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DELETE Removes:
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INSERT INTO Table (Col1, Col2) VALUES (Val1, Val2):
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To Update A Row’s Salary In Employees:
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DELETE FROM Table WHERE Condition:
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To Insert Multiple Rows At Once (Some Dialects Allow):
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Without WHERE In UPDATE Or DELETE:
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INSERT Can Be Combined With SELECT To:
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TRUNCATE TABLE Differs From DELETE Because:
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PRIMARY KEY Ensures:
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FOREIGN KEY Enforces:
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UNIQUE Constraint Ensures:
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NOT NULL Ensures:
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CHECK Constraint Allows:
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A Table Can Have How Many PRIMARY KEY Constraints?:
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FOREIGN KEY References:
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UNIQUE Differs From PRIMARY KEY In That:
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To Ensure Age > 0 In A Column, Use:
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Constraints Are Defined Usually In:
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A VIEW Is:
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CREATE VIEW Syntax Includes:
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A MATERIALIZED VIEW Is:
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Views Can Be Used To:
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To Refresh A Materialized View (In Systems That Support It):
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Dropping A View:
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Some Views Are Updatable If:
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A View Does Not Physically Store Data Except:
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To Ensure View Runs A Complex Query Efficiently Without Recalculating Each Time, Use:
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Views Can Be Used For Security By:
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An Index Is Used To:
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A Primary Key Usually Creates:
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Adding Too Many Indexes Can:
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A Clustered Index:
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Non-Clustered Index Stores:
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To Analyze Query Performance, One Might Use:
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Indexes Help SELECT Queries But Can Slow Down:
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A Good Candidate For Indexing Is:
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Removing Unused Indexes Can:
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Indexes Are Created By:
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A Window Function Is Defined Using:
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Window Functions Allow Calculations:
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PARTITION BY In Window Functions:
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ROW_NUMBER() Function:
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RANK() Vs ROW_NUMBER():
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LAG() And LEAD() Functions Allow:
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NTILE(N) Divides Rows Into:
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To Use Window Functions, OVER Clause Is Mandatory Because:
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Window Functions Do Not Collapse Rows Like GROUP BY. They:
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ORDER BY Inside OVER(…) Defines:
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A CTE Starts With:
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A CTE Is Defined For:
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CTEs Can Be Used To:
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A CTE Resembles A Derived Table, But:
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Recursive CTEs Allow:
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Syntax Of A Basic CTE:
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CTEs Are Not Stored Persistently; They Are:
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Recursive CTEs Need:
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CTEs Improve Readability Compared To:
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String Functions Like LENGTH() Or CHAR_LENGTH() Return:
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SUBSTRING(String, Start, Length) Extracts:
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UPPER() And LOWER() Functions Change String Case To:
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Date Functions Like NOW() Or CURRENT_DATE():
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EXTRACT(YEAR FROM Date) Returns:
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DATEADD Or ADD_MONTHS Are Used To:
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CASE Expression Allows:
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CASE WHEN Condition THEN Value ELSE Other END:
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String Functions Like CONCAT(S1,S2):
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COALESCE(Expr1, Expr2, …) Returns:
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A Stored Procedure Is:
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A Stored Function Differs From A Procedure By:
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CREATE PROCEDURE Syntax Varies By Dialect, But Generally Includes:
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Stored Procedures Can Improve Performance By:
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Functions Are Often Used In SELECT Statements Because:
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Stored Procedures Can Accept IN, OUT Parameters To:
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In PL/SQL Or T-SQL, You Can Write:
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To Drop A Stored Procedure:
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Stored Functions Must:
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Procedures And Functions Enhance:
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A Transaction Is:
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COMMIT Saves Changes Made During A Transaction:
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ROLLBACK Undoes:
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BEGIN Or START TRANSACTION Begins:
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Isolation Levels Define:
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A Common Isolation Level Is:
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Locking Is Used To Prevent:
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Deadlocks Occur When:
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COMMIT Ends A Transaction And Makes Changes:
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SAVEPOINT Allows:
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Partitioning A Table Means:
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Horizontal Partitioning Splits Data By:
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Vertical Partitioning Splits Data By:
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Sharding Is A Form Of Partitioning Where:
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Caching Query Results In Memory Can:
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vertical Partitioning Splits Data By:
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Table Partitioning Can Improve Performance By:
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Parallel Query Execution Means:
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Compression In Databases Can:
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Advanced Partitioning Strategies And Indexing Can Lead To:
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