Database - Interview Questions and Answers for 'Joins' | Search Interview Question - javasearch.buggybread.com
Javasearch.buggybread.com

Search Interview Questions


 More than 3000 questions in repository.
 There are more than 900 unanswered questions.
Click here and help us by providing the answer.
 Have a video suggestion.
Click Correct / Improve and please let us know.
Label / Company      Label / Company / Text

   



Database - Interview Questions and Answers for 'Joins' - 13 question(s) found - Order By Newest

Frequently asked in Cognizant ( Based on 2 feedback )
  Q1. What are Inner , Outer , Left and Right Joins in SQL ?Database
Ans. Inner join is the intersection of two tables on the condition defined by the where clause i.e will get records from both tables matched by a column.

Outer join is the union of two tables i.e will get all records from both tables and will put null in the columns where related records are not present.

Left Outer join is the left union of two tables i.e all records from the table on the left and values from the right table for related records else null for the columns from right table.

Right Outer join is the right union of two tables i.e all records from the table on the right and values from the left table for related records else null for the columns from left table.

 Help us improve. Please let us know the company, where you were asked this question :   

   Like         Discuss         Correct / Improve     sql  inner join  outer join  right join  left join     Asked in 24 Companies      basic        frequent


Not frequently asked as it was introduced with Java 8.
 Q2. What is StringJoiner ?Core Java
Ans. StringJoiner is a util method to construct a string with desired delimiter. This has been introduced with wef from Java 8.

Sample Code

StringJoiner strJoiner = new StringJoiner(".");
strJoiner.add("Buggy").add("Bread");
System.out.println(strJoiner); // prints Buggy.Bread


 Help us improve. Please let us know the company, where you were asked this question :   

   Like         Discuss         Correct / Improve     java   java8   java 8   string   stringjoiner


  Q3. What is a self Join and give an example of a self Join ?

or

What is self Join and What is it's purpose ?
Database
Ans. When a Table Join itself , it's a Self Join. For example - we like to know the pair of department names where first dept has lesser employees than the later.

Select D1.name , D2.name from Dept D1, Dept D2 where D1.employee_count < D2.employee_count

 Help us improve. Please let us know the company, where you were asked this question :   

   Like         Discuss         Correct / Improve     sql  joins  self join  self-join  Pair of employee names with first having lesser salary than later  Pair of department names where first dept has lesser employees than the later     Asked in 26 Companies      basic        frequent


 Q4. Difference between Inner and Outer Join ?Database
Ans. Inner join is the intersection of two tables on a particular columns whereas Outer Join is the Union of two tables.

 Help us improve. Please let us know the company, where you were asked this question :   

   Like         Discuss         Correct / Improve     sql   joins   inner join   outer join     Asked in 4 Companies      basic        frequent


Rarely asked as it was introduced with Java 8.
 Q5. Which of the following has been introduced with Java 8 ? a. StringBuffer b. StringBuilder c. StringFilter d. StringJoinerCore Java
Ans. StringJoiner

 Help us improve. Please let us know the company, where you were asked this question :   

   Like         Discuss         Correct / Improve     java   java8   java 8   string   stringjoiner


 Q6. If Table A has 100 records and Table B has 50 records , how many records will the equi join of Table generate ?SQL
Ans. It depends on the join condition.

 Help us improve. Please let us know the company, where you were asked this question :   

   Like         Discuss         Correct / Improve     equi join  sql join  database  sql


 Q7. If Table A has 100 records and Table B has 50 records , how many records will the left join of Table A with Table B generate ?SQL
Ans. 100 records

 Help us improve. Please let us know the company, where you were asked this question :   

   Like         Discuss         Correct / Improve     database  sql  sql joins   left join


 Q8. If Table A has 100 records and Table B has 50 records , how many records will the right join of Table A with Table B generate ?SQL
Ans. 50 records

 Help us improve. Please let us know the company, where you were asked this question :   

   Like         Discuss         Correct / Improve     database  sql  sql joins   right join


 Q9. If Table A has 0 records and Table B has 50 records , how many records will the equi join of Table generate ?SQL
Ans. 0 records

 Help us improve. Please let us know the company, where you were asked this question :   

   Like         Discuss         Correct / Improve     database  sql  sql joins   equi join


 Q10. What is Left Outer Join ?Database
Ans. It returns all the rows form the left table and matches the rows in both tables.

 Help us improve. Please let us know the company, where you were asked this question :   

   Like         Discuss         Correct / Improve     database   database joins   left outer join  sql     Asked in 2 Companies


 Q11. Describe SQL JoinsDatabase
Ans. Oracle having following types of joins these are also called 8i joins. There are:

1. Equi (or) Inner join
2. Non Equi join
3.Self join
4.Outer join

Oracle also support the 9i (or) ANSI standard joins.There are:

1.Inner join
2.Left outer join
3.Right outer join
4.Full outer join
5.Natural join

 Help us improve. Please let us know the company, where you were asked this question :   

   Like         Discuss         Correct / Improve     sql joins  sql     Asked in 2 Companies


 Q12. create an SQL query across multiple tables involving outer joins Database
Ans. Select * from table1 t1Left outer join table2 t2 on t1.tid = t2.id

 Help us improve. Please let us know the company, where you were asked this question :   

   Like         Discuss         Correct / Improve     sql query  database  outer joins     Asked in 2 Companies


 Q13. What is the minimum number of tables required to perform a SQL join?Database
Ans. 1 , We can do self join


 Help us improve. Please let us know the company, where you were asked this question :   

   Like         Discuss         Correct / Improve     sql join     Asked in 1 Companies


 Q14. In majority of the cases, the following join will give maximum number of results ?Database
a. Inner Join
b. Outer Join
c. Left Join
d. Right Join

Ans.b. Outer Join

 Q15. Which if the following is true for SQL Joins ?Database
a. Left Join and Right Join gives equal number of Results
b. Outer Join and Inner Join gives equal number of Results
c. Inner Join gives maximum number of results records
d. Inner Join gives minimum number of result records

Ans.d. Inner Join gives minimum number of result records


Help us and Others Improve. Please let us know the questions asked in any of your previous interview.

Any input from you will be highly appreciated and It will unlock the application for 10 more requests.

Company Name:
Questions Asked: