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PRIMARY KEY Ensures: · SQL

Home / Practice / SQL Quiz (200 Questions)

PRIMARY KEY Ensures:

#111 · 111 of 199

SQL Quiz (200 Questions)

199 exercises

01What Does SQL Stand For?Free
02Which Part Of SQL Is Primarily Used To Retrieve Data?Free
03SQL Is Programming Language For Storing And Processing Information In?Free
04Which Keyword Begins A Query That Retrieves Data From A Table?Free
05SQL Is Considered What Type Of Language?Free
06Which Of The Following Is A Common Relational Database System?Free
07Which Keyword Removes Duplicates In A SELECT Statement?Free
08Which Statement Changes Data In A Database?Free
09n SQL, Which Symbol Is Commonly Used As A Wildcard In Strings?Free
10Which Command Is Used To Remove Rows From A Table?Free
11Which Clause Specifies The Source Table(S) In A Query?Locked
12Which Keyword Selects All Columns From A Table?Locked
13To Select A Literal String “Hello”, You Can Write:Locked
14To Rename A Column In The Result Set, Use:Locked
15If You Omit FROM, Selecting From Where Is Possible In Standard SQL?Locked
16To Choose Columns “Name” And “Age” From Table “Persons”:Locked
17A SELECT Statement Without A WHERE Clause Returns:Locked
18To Avoid Specifying A Table Alias, You Can:Locked
19Which Of These Is A Valid SELECT Syntax?Locked
20Using SELECT Without Specifying Columns Returns:Locked
21The WHERE Clause Is Used To:Locked
22To Select Rows Where Age > 18:Locked
23To Match Rows Where Name Starts With ‘A’:Locked
24To Select Rows Where City Is Either ‘Paris’ Or ‘London’:Locked
25The WHERE Clause Is Placed:Locked
26To Find Rows Where Salary Is NOT 5000:Locked
27Which Operator Checks For NULL Values?Locked
28To Exclude Rows With Age = 30:Locked
29To Use A Pattern To Filter Rows Containing ‘Abc’ Anywhere In Name:Locked
30To Filter Rows Where Price Is Between 10 And 20 Inclusive:Locked
31Which Function Returns The Number Of Rows?Locked
32SUM() Function Is Used To:Locked
33MIN() Function Returns:Locked
34MAX() Function Returns:Locked
35AVG() Function Returns:Locked
36COUNT(*) Differs From COUNT(Column) By:Locked
37To Get Total Sales From ‘Orders’ Table With ‘Amount’ Column:Locked
38To Find The Lowest Salary In Employees Table:Locked
39To Count Rows Ignoring NULL In Column ‘Age’:Locked
40Which Function Can Remove Duplicates When Counting Distinct Values?Locked
41GROUP BY Is Used To:Locked
42GROUP BY Must Be Used With:Locked
43HAVING Clause Filters Rows After:Locked
44To Find Total Sales Per Department:Locked
45HAVING Is Used To Filter Groups, For Example Groups With SUM(Sales)>1000:Locked
46If A SELECT Uses GROUP BY, Columns Not Aggregated Must Be:Locked
47Average Salary By Job_title But Only Show Groups With Avg>5000:Locked
48Without GROUP BY, HAVING Acts Like WHERE, But Standard SQL Requires:Locked
49Count Employees Per Department And Only Show Departments With Count>10:Locked
50You Cannot Use HAVING Without What?Locked
51ORDER BY Is Used To:Locked
52By Default ORDER BY Sorts In:Locked
53To Sort By Name Ascending And Age Descending:Locked
54ORDER BY Must Come:Locked
55To Sort By A Column Not In SELECT, Generally:Locked
56To Sort By Multiple Columns, Separate By:Locked
57To Get Alphabetical Order On ‘Name’:Locked
58To Reverse The Sorting Order:Locked
59If No ORDER BY Specified, Order Of Rows Is:Locked
60ORDER BY Can Sort By Column Position Using:Locked
61INNER JOIN Returns:Locked
62LEFT JOIN Returns:Locked
63RIGHT JOIN Returns:Locked
64FULL OUTER JOIN Returns:Locked
65To Join ‘Orders’ And ‘Customers’ Where Orders.cust_id=Customers.id:Locked
66INNER JOIN Is Also Called:Locked
67To Get All Customers Even If They Have No Orders:Locked
68CROSS JOIN Returns:Locked
69To Filter Joined Results, Use Conditions In:Locked
70If You Want All Rows From Both Tables With No Match Replaced By NULLs:Locked
71A Subquery Is:Locked
72Subqueries Are Often Used In:Locked
73A Scalar Subquery Returns:Locked
74To Find Rows With Value Greater Than The Average, Use:Locked
75A Derived Table Is A Subquery Used:Locked
76A Subquery Returning Multiple Values Can Be Used With:Locked
77Correlated Subqueries:Locked
78To Use A Subquery As A Column List:Locked
79Subqueries Can Appear In:Locked
80A Derived Table Must Have:Locked
81UNION Combines:Locked
82UNION Requires:Locked
83UNION By Default Removes Duplicates. To Keep Duplicates Use:Locked
84INTERSECT Returns:Locked
85EXCEPT Returns:Locked
86Set Operations Typically Require:Locked
87UNION ALL Vs UNION Differs By:Locked
88INTERSECT And EXCEPT Might Not Be Supported By All SQL Dialects. A Common Replacement For INTERSECT Is:Locked
89Set Operators Combine Results Of Multiple SELECTs. The Correct Syntax Usually Is:Locked
90EXCEPT Is Sometimes Known As:Locked
91CREATE TABLE Is Used To:Locked
92B. Removes table structure and dataLocked
93ALTER TABLE Is Used To:Locked
94To Remove A Column From A Table:Locked
95CREATE TABLE Syntax Generally Includes:Locked
96To Rename A Table:Locked
97To Add A New Column:Locked
98DDL Statements Like CREATE, DROP, ALTER Usually:Locked
99To Completely Remove A Table And Its Data:Locked
100To Remove All Rows But Keep Table Structure:Locked
101INSERT Is Used To:Locked
102UPDATE Changes:Locked
103DELETE Removes:Locked
104INSERT INTO Table (Col1, Col2) VALUES (Val1, Val2):Locked
105To Update A Row’s Salary In Employees:Locked
106DELETE FROM Table WHERE Condition:Locked
107To Insert Multiple Rows At Once (Some Dialects Allow):Locked
108Without WHERE In UPDATE Or DELETE:Locked
109INSERT Can Be Combined With SELECT To:Locked
110TRUNCATE TABLE Differs From DELETE Because:Locked
111PRIMARY KEY Ensures:Locked
112FOREIGN KEY Enforces:Locked
113UNIQUE Constraint Ensures:Locked
114NOT NULL Ensures:Locked
115CHECK Constraint Allows:Locked
116A Table Can Have How Many PRIMARY KEY Constraints?:Locked
117FOREIGN KEY References:Locked
118UNIQUE Differs From PRIMARY KEY In That:Locked
119To Ensure Age > 0 In A Column, Use:Locked
120Constraints Are Defined Usually In:Locked
121A VIEW Is:Locked
122CREATE VIEW Syntax Includes:Locked
123A MATERIALIZED VIEW Is:Locked
124Views Can Be Used To:Locked
125To Refresh A Materialized View (In Systems That Support It):Locked
126Dropping A View:Locked
127Some Views Are Updatable If:Locked
128A View Does Not Physically Store Data Except:Locked
129To Ensure View Runs A Complex Query Efficiently Without Recalculating Each Time, Use:Locked
130Views Can Be Used For Security By:Locked
131An Index Is Used To:Locked
132A Primary Key Usually Creates:Locked
133Adding Too Many Indexes Can:Locked
134A Clustered Index:Locked
135Non-Clustered Index Stores:Locked
136To Analyze Query Performance, One Might Use:Locked
137Indexes Help SELECT Queries But Can Slow Down:Locked
138A Good Candidate For Indexing Is:Locked
139Removing Unused Indexes Can:Locked
140Indexes Are Created By:Locked
141A Window Function Is Defined Using:Locked
142Window Functions Allow Calculations:Locked
143PARTITION BY In Window Functions:Locked
144ROW_NUMBER() Function:Locked
145RANK() Vs ROW_NUMBER():Locked
146LAG() And LEAD() Functions Allow:Locked
147NTILE(N) Divides Rows Into:Locked
148To Use Window Functions, OVER Clause Is Mandatory Because:Locked
149Window Functions Do Not Collapse Rows Like GROUP BY. They:Locked
150ORDER BY Inside OVER(…) Defines:Locked
151A CTE Starts With:Locked
152A CTE Is Defined For:Locked
153CTEs Can Be Used To:Locked
154A CTE Resembles A Derived Table, But:Locked
155Recursive CTEs Allow:Locked
156Syntax Of A Basic CTE:Locked
158CTEs Are Not Stored Persistently; They Are:Locked
159Recursive CTEs Need:Locked
160CTEs Improve Readability Compared To:Locked
161String Functions Like LENGTH() Or CHAR_LENGTH() Return:Locked
162SUBSTRING(String, Start, Length) Extracts:Locked
163UPPER() And LOWER() Functions Change String Case To:Locked
164Date Functions Like NOW() Or CURRENT_DATE():Locked
165EXTRACT(YEAR FROM Date) Returns:Locked
166DATEADD Or ADD_MONTHS Are Used To:Locked
167CASE Expression Allows:Locked
168CASE WHEN Condition THEN Value ELSE Other END:Locked
169String Functions Like CONCAT(S1,S2):Locked
170COALESCE(Expr1, Expr2, …) Returns:Locked
171A Stored Procedure Is:Locked
172A Stored Function Differs From A Procedure By:Locked
173CREATE PROCEDURE Syntax Varies By Dialect, But Generally Includes:Locked
174Stored Procedures Can Improve Performance By:Locked
175Functions Are Often Used In SELECT Statements Because:Locked
176Stored Procedures Can Accept IN, OUT Parameters To:Locked
177In PL/SQL Or T-SQL, You Can Write:Locked
178To Drop A Stored Procedure:Locked
179Stored Functions Must:Locked
180Procedures And Functions Enhance:Locked
181A Transaction Is:Locked
182COMMIT Saves Changes Made During A Transaction:Locked
183ROLLBACK Undoes:Locked
184BEGIN Or START TRANSACTION Begins:Locked
185Isolation Levels Define:Locked
186A Common Isolation Level Is:Locked
187Locking Is Used To Prevent:Locked
188Deadlocks Occur When:Locked
189COMMIT Ends A Transaction And Makes Changes:Locked
190SAVEPOINT Allows:Locked
191Partitioning A Table Means:Locked
192Horizontal Partitioning Splits Data By:Locked
193Vertical Partitioning Splits Data By:Locked
194Sharding Is A Form Of Partitioning Where:Locked
195Caching Query Results In Memory Can:Locked
196vertical Partitioning Splits Data By:Locked
197Table Partitioning Can Improve Performance By:Locked
198Parallel Query Execution Means:Locked
199Compression In Databases Can:Locked
200Advanced Partitioning Strategies And Indexing Can Lead To:Locked

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All exercises in SQL Quiz (200 Questions)199

SQL Quiz (200 Questions)

199 exercises

01What Does SQL Stand For?Free
02Which Part Of SQL Is Primarily Used To Retrieve Data?Free
03SQL Is Programming Language For Storing And Processing Information In?Free
04Which Keyword Begins A Query That Retrieves Data From A Table?Free
05SQL Is Considered What Type Of Language?Free
06Which Of The Following Is A Common Relational Database System?Free
07Which Keyword Removes Duplicates In A SELECT Statement?Free
08Which Statement Changes Data In A Database?Free
09n SQL, Which Symbol Is Commonly Used As A Wildcard In Strings?Free
10Which Command Is Used To Remove Rows From A Table?Free
11Which Clause Specifies The Source Table(S) In A Query?Locked
12Which Keyword Selects All Columns From A Table?Locked
13To Select A Literal String “Hello”, You Can Write:Locked
14To Rename A Column In The Result Set, Use:Locked
15If You Omit FROM, Selecting From Where Is Possible In Standard SQL?Locked
16To Choose Columns “Name” And “Age” From Table “Persons”:Locked
17A SELECT Statement Without A WHERE Clause Returns:Locked
18To Avoid Specifying A Table Alias, You Can:Locked
19Which Of These Is A Valid SELECT Syntax?Locked
20Using SELECT Without Specifying Columns Returns:Locked
21The WHERE Clause Is Used To:Locked
22To Select Rows Where Age > 18:Locked
23To Match Rows Where Name Starts With ‘A’:Locked
24To Select Rows Where City Is Either ‘Paris’ Or ‘London’:Locked
25The WHERE Clause Is Placed:Locked
26To Find Rows Where Salary Is NOT 5000:Locked
27Which Operator Checks For NULL Values?Locked
28To Exclude Rows With Age = 30:Locked
29To Use A Pattern To Filter Rows Containing ‘Abc’ Anywhere In Name:Locked
30To Filter Rows Where Price Is Between 10 And 20 Inclusive:Locked
31Which Function Returns The Number Of Rows?Locked
32SUM() Function Is Used To:Locked
33MIN() Function Returns:Locked
34MAX() Function Returns:Locked
35AVG() Function Returns:Locked
36COUNT(*) Differs From COUNT(Column) By:Locked
37To Get Total Sales From ‘Orders’ Table With ‘Amount’ Column:Locked
38To Find The Lowest Salary In Employees Table:Locked
39To Count Rows Ignoring NULL In Column ‘Age’:Locked
40Which Function Can Remove Duplicates When Counting Distinct Values?Locked
41GROUP BY Is Used To:Locked
42GROUP BY Must Be Used With:Locked
43HAVING Clause Filters Rows After:Locked
44To Find Total Sales Per Department:Locked
45HAVING Is Used To Filter Groups, For Example Groups With SUM(Sales)>1000:Locked
46If A SELECT Uses GROUP BY, Columns Not Aggregated Must Be:Locked
47Average Salary By Job_title But Only Show Groups With Avg>5000:Locked
48Without GROUP BY, HAVING Acts Like WHERE, But Standard SQL Requires:Locked
49Count Employees Per Department And Only Show Departments With Count>10:Locked
50You Cannot Use HAVING Without What?Locked
51ORDER BY Is Used To:Locked
52By Default ORDER BY Sorts In:Locked
53To Sort By Name Ascending And Age Descending:Locked
54ORDER BY Must Come:Locked
55To Sort By A Column Not In SELECT, Generally:Locked
56To Sort By Multiple Columns, Separate By:Locked
57To Get Alphabetical Order On ‘Name’:Locked
58To Reverse The Sorting Order:Locked
59If No ORDER BY Specified, Order Of Rows Is:Locked
60ORDER BY Can Sort By Column Position Using:Locked
61INNER JOIN Returns:Locked
62LEFT JOIN Returns:Locked
63RIGHT JOIN Returns:Locked
64FULL OUTER JOIN Returns:Locked
65To Join ‘Orders’ And ‘Customers’ Where Orders.cust_id=Customers.id:Locked
66INNER JOIN Is Also Called:Locked
67To Get All Customers Even If They Have No Orders:Locked
68CROSS JOIN Returns:Locked
69To Filter Joined Results, Use Conditions In:Locked
70If You Want All Rows From Both Tables With No Match Replaced By NULLs:Locked
71A Subquery Is:Locked
72Subqueries Are Often Used In:Locked
73A Scalar Subquery Returns:Locked
74To Find Rows With Value Greater Than The Average, Use:Locked
75A Derived Table Is A Subquery Used:Locked
76A Subquery Returning Multiple Values Can Be Used With:Locked
77Correlated Subqueries:Locked
78To Use A Subquery As A Column List:Locked
79Subqueries Can Appear In:Locked
80A Derived Table Must Have:Locked
81UNION Combines:Locked
82UNION Requires:Locked
83UNION By Default Removes Duplicates. To Keep Duplicates Use:Locked
84INTERSECT Returns:Locked
85EXCEPT Returns:Locked
86Set Operations Typically Require:Locked
87UNION ALL Vs UNION Differs By:Locked
88INTERSECT And EXCEPT Might Not Be Supported By All SQL Dialects. A Common Replacement For INTERSECT Is:Locked
89Set Operators Combine Results Of Multiple SELECTs. The Correct Syntax Usually Is:Locked
90EXCEPT Is Sometimes Known As:Locked
91CREATE TABLE Is Used To:Locked
92B. Removes table structure and dataLocked
93ALTER TABLE Is Used To:Locked
94To Remove A Column From A Table:Locked
95CREATE TABLE Syntax Generally Includes:Locked
96To Rename A Table:Locked
97To Add A New Column:Locked
98DDL Statements Like CREATE, DROP, ALTER Usually:Locked
99To Completely Remove A Table And Its Data:Locked
100To Remove All Rows But Keep Table Structure:Locked
101INSERT Is Used To:Locked
102UPDATE Changes:Locked
103DELETE Removes:Locked
104INSERT INTO Table (Col1, Col2) VALUES (Val1, Val2):Locked
105To Update A Row’s Salary In Employees:Locked
106DELETE FROM Table WHERE Condition:Locked
107To Insert Multiple Rows At Once (Some Dialects Allow):Locked
108Without WHERE In UPDATE Or DELETE:Locked
109INSERT Can Be Combined With SELECT To:Locked
110TRUNCATE TABLE Differs From DELETE Because:Locked
111PRIMARY KEY Ensures:Locked
112FOREIGN KEY Enforces:Locked
113UNIQUE Constraint Ensures:Locked
114NOT NULL Ensures:Locked
115CHECK Constraint Allows:Locked
116A Table Can Have How Many PRIMARY KEY Constraints?:Locked
117FOREIGN KEY References:Locked
118UNIQUE Differs From PRIMARY KEY In That:Locked
119To Ensure Age > 0 In A Column, Use:Locked
120Constraints Are Defined Usually In:Locked
121A VIEW Is:Locked
122CREATE VIEW Syntax Includes:Locked
123A MATERIALIZED VIEW Is:Locked
124Views Can Be Used To:Locked
125To Refresh A Materialized View (In Systems That Support It):Locked
126Dropping A View:Locked
127Some Views Are Updatable If:Locked
128A View Does Not Physically Store Data Except:Locked
129To Ensure View Runs A Complex Query Efficiently Without Recalculating Each Time, Use:Locked
130Views Can Be Used For Security By:Locked
131An Index Is Used To:Locked
132A Primary Key Usually Creates:Locked
133Adding Too Many Indexes Can:Locked
134A Clustered Index:Locked
135Non-Clustered Index Stores:Locked
136To Analyze Query Performance, One Might Use:Locked
137Indexes Help SELECT Queries But Can Slow Down:Locked
138A Good Candidate For Indexing Is:Locked
139Removing Unused Indexes Can:Locked
140Indexes Are Created By:Locked
141A Window Function Is Defined Using:Locked
142Window Functions Allow Calculations:Locked
143PARTITION BY In Window Functions:Locked
144ROW_NUMBER() Function:Locked
145RANK() Vs ROW_NUMBER():Locked
146LAG() And LEAD() Functions Allow:Locked
147NTILE(N) Divides Rows Into:Locked
148To Use Window Functions, OVER Clause Is Mandatory Because:Locked
149Window Functions Do Not Collapse Rows Like GROUP BY. They:Locked
150ORDER BY Inside OVER(…) Defines:Locked
151A CTE Starts With:Locked
152A CTE Is Defined For:Locked
153CTEs Can Be Used To:Locked
154A CTE Resembles A Derived Table, But:Locked
155Recursive CTEs Allow:Locked
156Syntax Of A Basic CTE:Locked
158CTEs Are Not Stored Persistently; They Are:Locked
159Recursive CTEs Need:Locked
160CTEs Improve Readability Compared To:Locked
161String Functions Like LENGTH() Or CHAR_LENGTH() Return:Locked
162SUBSTRING(String, Start, Length) Extracts:Locked
163UPPER() And LOWER() Functions Change String Case To:Locked
164Date Functions Like NOW() Or CURRENT_DATE():Locked
165EXTRACT(YEAR FROM Date) Returns:Locked
166DATEADD Or ADD_MONTHS Are Used To:Locked
167CASE Expression Allows:Locked
168CASE WHEN Condition THEN Value ELSE Other END:Locked
169String Functions Like CONCAT(S1,S2):Locked
170COALESCE(Expr1, Expr2, …) Returns:Locked
171A Stored Procedure Is:Locked
172A Stored Function Differs From A Procedure By:Locked
173CREATE PROCEDURE Syntax Varies By Dialect, But Generally Includes:Locked
174Stored Procedures Can Improve Performance By:Locked
175Functions Are Often Used In SELECT Statements Because:Locked
176Stored Procedures Can Accept IN, OUT Parameters To:Locked
177In PL/SQL Or T-SQL, You Can Write:Locked
178To Drop A Stored Procedure:Locked
179Stored Functions Must:Locked
180Procedures And Functions Enhance:Locked
181A Transaction Is:Locked
182COMMIT Saves Changes Made During A Transaction:Locked
183ROLLBACK Undoes:Locked
184BEGIN Or START TRANSACTION Begins:Locked
185Isolation Levels Define:Locked
186A Common Isolation Level Is:Locked
187Locking Is Used To Prevent:Locked
188Deadlocks Occur When:Locked
189COMMIT Ends A Transaction And Makes Changes:Locked
190SAVEPOINT Allows:Locked
191Partitioning A Table Means:Locked
192Horizontal Partitioning Splits Data By:Locked
193Vertical Partitioning Splits Data By:Locked
194Sharding Is A Form Of Partitioning Where:Locked
195Caching Query Results In Memory Can:Locked
196vertical Partitioning Splits Data By:Locked
197Table Partitioning Can Improve Performance By:Locked
198Parallel Query Execution Means:Locked
199Compression In Databases Can:Locked
200Advanced Partitioning Strategies And Indexing Can Lead To:Locked