We all know how to get a distinct count of a column. It can be done with COUNT(DISTINCT column_name). For example:
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We all know how to get a distinct count of a column. It can be done with COUNT(DISTINCT column_name). For example:
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1 2 3 4 |
This extends Common Table Expressions (i.e. CTE) in SQL using the “WITH” clause. You can try the example on DB Fiddle. Use MySQL v8.0 or later. Scenario: 1 Given a …
One of the common SQL interview questions is to quiz your understanding of SQL joins. In this let’s look at joins example with two scenarios.
Joins can …
If you want to learn the basics of SQL analytics function, first read SQL analytic functions interview questions – Part 1 | SQL analytic functions interview questions – Part 2…
The below SQL problem can be practiced on MySQL database at db-fiddle or database of your choice. Q1. Given the below data, how will you find the last non null …
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 …
This continues 25+ SQL interview questions & answers – beginner
Q16. Why do you have CASE statements in SQL?
A16. CASE statements in SQL are similar to IF and ELSE …
Setup the data on db-fiddle MySQL V8.0 to practice. This question is based on the LeetCode SQL problem Q. Given the below input: login table
The below SQL problem can be practiced on MySQL database at db-fiddle or database of your choice. Use latest version from the drop down.
Q1. Given the below data, how …
The data analysts & engineers will often be faced with the below SQL scenario at work. It is also often asked in job interviews. This solution uses SQL analytical functions …
This extends 50+ SQL scenarios based interview Q&As – identifying consecutive records – job status repetition. A popular SQL coding interview question. Setup the data on db-fiddle MySQL V8.0 to …
Q01. What is a Non-Equi Join? A01. A Non-Equi Join in SQL that uses operators other than equality operator (i.e. ‘=’), like , = to join two tables. Q02. When …
This post covers SQL examples to perform quality checks, clean data and profile data. Q01. What is Data Cleaning? Can SQL do data cleaning? A01. Data cleaning is the process …
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