SQL interview Questions & Answers is a must for any developer as all non-trivial applications need to talk to a database with CRUD operations. Q3 – Q15 are very popular with the interviewers. If you want to quickly practice your SQL skills try DB Fiddle or install MySQL locally as...
Q1 How will you go about identifying duplicate records in a table?
A1 The following SQL query will do the trick.
Note: Interviewer is testing if you understand that the aggregate queries need to have a “GROUP BY”
…
Common Table Expressions or CTE’s for short are used in SQL to simplify complex joins and subqueries, and to provide a means to query hierarchical data such as an organisational chart. This was also introduced in MySQL 8 – Using https://www.db-fiddle.com/. … Read more ›...
Q1. What is a temporal table? A1. Temporal tables store and maintain information with respect to time. This tracks data changes, and enables us to maintain and manage the history of the data in a table. … Read more ›...
This question can reveal a lot about your ability to write SQL queries as different approaches can be used and there will be drill down on pros and cons of each approach. Q1. Given the following SQL, how do you retrieve the latest records by updated date for each user?...
Data Engineers & analysts must know the Window functions as it is a powerful tool to analyse the data. This post compliments “Apache Spark window functions” focus on using SQL on MySQL server covered. You can also apply this on Big Data SQL engines like Hive &
…
Mechanical Engineer to self-taught Java engineer within 2 years & a freelancer within 3 years. Freelancing since 2003. Preparation empowered me to attend 190+ job interviews & choose from 150+ job offers with sought-after contract rates. Author of the book “Java/J2EE job interview companion“, which sold 35K+ copies & superseded by this site with 2,050+ registered users. Amazon.com profile | Reviews | LinkedIn | LinkedIn Group | YouTube
Contact us: java-interview@hotmail.com
