Javarevisited: database interview questions

Showing posts with label database interview questions. Show all posts

Showing posts with label database interview questions. Show all posts

Wednesday, October 2, 2024

Difference between char, varchar, nchar and nvarchar data types in SQL Server? Example

What is the difference between char and varchar in SQL, followed by nchar and nvarchar , is one of the popular SQL interview questions , an...

Thursday, September 26, 2024

How to use EXISTS and NOT Exists in SQL? Example Query and Tutorial

Hello Guys, you might have heard about how useful the EXISTS clause is helpful in writing sophisticated queries. Still, at the same time, I...

Monday, September 16, 2024

Difference between LEFT and RIGHT OUTER Joins in SQL - MySQL Join example

There are two kinds of OUTER joins in SQL, LEFT OUTER join and RIGHT OUTER join. The main difference between RIGHT OUTER joins and ...

Friday, July 14, 2023

How to find duplicate records in a table on database - SQL tips

How to find duplicate records in a table is a popular SQL interview questions which have been asked as many times as difference between tr...

Thursday, July 13, 2023

How to find second highest or maximum salary of Employee in SQL - Interview question

How to find the second highest or second maximum salary of an Employee is one of the most frequently asked SQL interview questions similar...

Tuesday, May 23, 2023

Difference between Truncate and Delete in SQL? Example

Truncate and delete in SQL are two commands which are used to remove or delete data from a table. Though quite basic in nature both SQL co...

Monday, May 22, 2023

Difference between Clustered Index and Non Clustered Index in SQL - Example

In the SQL Server database, there are mainly two types of indexes, Clustered index, and the Non-Clustered index and difference between Clu...

Difference between Primary key vs Foreign key in table – SQL Tutorial Example

The main difference between the Primary key and the Foreign key in a table is that it’s the same column that behaves as the primary key in...

What is Referential Integrity in Database or SQL - MySQL Example Tutorial

Referential Integrity is a set of constraints applied to foreign keys which prevents entering a row in the child table (where you have the...

Thursday, May 11, 2023

How to Add, Modify and Drop Column with Default Value, NOT NULL Constraint – MySQL Example

How to add a column in the existing table with a default value is another popular SQL interview question asked for Junior level program...

Tuesday, January 31, 2023

How to Create Auto Incremented Identity Column in SQL Server, MySQL, and Oracle? Example

Automatic incremented ID, Sequence, or Identity columns are those columns in any table whose value is automatically incremented by databas...

Thursday, June 16, 2022

Difference between WHERE vs HAVING clause in SQL - GROUP BY Comparison with Example

What is the difference between WHERE and HAVING clause in SQL is one of the most popular questions asked on SQL and database intervi...

Friday, October 29, 2021

How to Split String in SQL Server and Sybase? Example Tutorial

Sometimes we need to split a long comma-separated String in a Stored procedure e.g. Sybase or SQL Server stored procedures. It's quite...

Friday, August 6, 2021

How to join three tables in SQL query – MySQL Example

Three tables JOIN Example SQL Joining three tables in a single SQL query can be very tricky if you are not good with the concept of SQL J...

SQL Query to Find All Table Names on a Database With MySQL and SQL Server Examples

How do you find names of all tables in a database is a recent SQL interview question asked to one of my friends. There are many ways to ...

Thursday, August 5, 2021

How to write SubQuery in SQL? Correlated vs Noncorrelated Sub Query Example

Hello guys, if you are struggling to write a sub query in SQL and need some guidance then you have come to the right place. In this articl...