How to use the GROUP BY clause on multiple columns in SQL?
How to use the GROUP BY clause on multiple columns in SQL?
SQL
SQL tutorials from Machine Learning Plus: hands-on guides with worked examples and code you can read, copy and run. Start with the fundamentals and work through to the applied posts in the SQL track.
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How to sort multiple columns in SQL and in different directions?
How to sort multiple columns in SQL and in different directions?
How to count the number of work days between two dates?
How to count the number of work days between two dates?
How to compute maximum of multiple columns, aks row wise max?
How to compute maximum of multiple columns, aks row wise max?
What is the difference between CROSS JOIN and INNER JOIN in SQL?
Let's understand the difference between CROSS JOIN and INNER JOIN with example
How to get a list of dates between two dates in SQL?
Let's see how to get a list of dates between two dates in SQL using an example. We will explore alternate solutions as well.
How to get records from one table that does not exist in another?
How to get records from one table that does not exist in another?
How to exclude a column using select * except column?
How to exclude a column using select * except column in SQL? Let's also see some work arounds.
How to access the “previous row” value in a SELECT statement in SQL?
Let's see how to access the 'previous row' value in a SELECT statement in SQL?
What is the difference between UNION and UNION ALL in SQL?
Let's understand the difference between UNION and UNION ALL with an example
How to use GROUP BY to concatenate strings in MySQL and SQL Server?
How to use GROUP BY to concatenate strings in MySQL and SQL Server?
How to find duplicate values in SQL Table?
Let's see how to find duplicate values in an SQL table.
How to return results only if value exists in SQL?
You have a table with a column where some rows contain NULL values or empty strings. You want to retrieve rows where this column has a value (i.e...
How to get top n results in each ‘group by’ group in SQL?
Let's see how to get top n results in each 'group by' group in SQL. You have a table with multiple records. For each distinct value in each 'group...
How to concatenate multiple rows into one field in MySQL?
Let's see how to concatenate multiple rows into one field in MySQL?
What is the difference between INNER JOIN, OUTER JOIN and FULL OUTER JOIN?
Understand the difference between INNER JOIN, OUTER JOIN and FULL OUTER JOIN with examples and compare the results.
How to select a random row using SQL?
Let's see how to select a random row from large tables efficiently using SQL
How to randomly select rows from a large table in MySQL super fast?
Let's see how to randomly select rows from a large table quick and efficiently in SQL
How to escape a single quote in SQL Server?
Let's look at how to escape a single quote in SQL Server, with a solution that is also reproducible in MySQL
How to efficiently convert rows to columns in SQL?
Learn how to efficiently convert rows to columns in SQL using PIVOT and CASE statements. Includes example problem, input table, and working solutions.
How to split values to multiple rows in SQL?
Let's see how to split values to multiple rows in SQL with an example problem and working solution.
How to remove duplicate rows in MySQL?
Given a table in MySQL, how do you remove duplicate rows? Let's see how to solve this with an example and solutions.
How to insert into a table or update if exists in MySQL?
Learn how to insert into a table or update if exists in MySQL and SQL Server. You need to calculate a running total in SQL Server and provide a...
How to get the rows which have the max value for a column for each group in another column in SQL?
Learn how to get the rows which have the max value for a column for each group in another column
How to do a FULL OUTER JOIN in MySQL?
Let's understand how to do a FULL OUTER JOIN in MySQL
How to concatenate text from multiple rows into a single text string in MySQL?
Learn How to concatenate text from multiple rows into a single text string in MySQL
How to calculate running total in SQL Server?
Let's see how to calculate running total in SQL Server
How to switch rows and columns in SQL?
How to switch rows and columns in SQL? Let's transpose so the rows become columns and columns as rows.
How to retrieve the last record in each group in SQL?
How to retrieve the last record in each group in SQL: the problem, the input table, the desired output and three solutions, each with an explanation...
How to get the top 1 row of each group in SQL?
How to get the top 1 row of each group in SQL: the problem, the input table, the desired output and three solutions, each with an explanation of how...
SQL Window Function Exercises and Solutions – Set 2
SQL window function exercises is designed to challenge your SQL muscle and help internalize data wrangling using window functions in SQL.
How to transpose columns to rows in SQL?
Let's see how to transpose columns to rows in SQL. That is, how to reshape the table so that certain columns of a table are moved to rows.
How to select only rows with max value on a column?
How to select only rows with max value on a column for each distinct value in another categorical column in MySQL?
How to select first row in each ‘Group By’ group?
How to select first row in each 'Group By' group? Let's understand with example problem and solutions.
SQL Window Functions Exercises – Practice to perfection
SQL window functions is considered a _'hard'_ concept in SQL. This set of exercises is designed to challenge your SQL muscle and help internalize...
SQL Window Functions – Made simple and intuitive
SQL window functions is one of the advanced concepts, understanding which will give you the ability to do complex data wrangling and transformations...
SQL Subquery – How to write subqueries using simple examples
SQL Subquery, also known as inner queries or nested queries, are used to query data from one or more tables and then used in another SQL statement.
SQL Tutorial – A Simple and Intuitive Guide to the Structured Query Language
SQL, short for Structured Query Language is a programming language used to communicate with databases and do various types of Data wrangling...
SQL Operators – Understanding SQL Operators with Examples and Syntax
SQL Operators - Understanding SQL Operators with Examples and Syntax
SQL SELECT INTO – Understanding the “SELECT INTO” Statement
SQL SELECT INTO a single command, you can accomplish two tasks of create a new table and fill it with data from an existing table.
SQL Primary Key: The Cornerstone of Database Integrity
Primary Key a cornerstone for maintaining data integrity and building complex database relationships.
SQL Null Functions – Understanding SQL Null Functions
Understanding SQL NULL functions, explaining their syntax and illustrating their use with practical examples.
SQL Insert Into Select – A Comprehensive Guide on SQL Insert Into Select Statement
Deep dive into a detailed discussion about the SQL Insert Into Select statement.
SQL Foreign Key – Understanding SQL Foreign Key, Syntax and Examples
Use of foreign keys in SQL enhances the relationship between tables and ensures data integrity.
SQL DROP TABLE – An Expert’s Guide to SQL DROP TABLE Command
SQL DROP TABLE - An Expert's Guide to SQL DROP TABLE Command
SQL CREATE TABLE – The Ultimate Guide to SQL CREATE TABLE Statement
SQL CREATE TABLE the intricacies of this important command, learn about its syntax, and run through an example of how to use it.
SQL Comments – A Deep Dive into SQL Comments
Exploring SQL comments a seemingly minor, but crucial aspect of SQL programming.
SQL CASE – A Detailed Overview and Understanding SQL CASE Expression
Deep dive into the SQL CASE expression. You will explore its syntax, uses, and provide examples to illustrate its applications.
SQL EXISTS – A Comprehensive Guide on SQL EXISTS
Dive deep into one of SQL's most useful yet under-utilized functionalities: the EXISTS clause. This powerful tool can make your queries not only more...
SQL ANY, ALL Operators – A Comprehensive Guide
The SQL ANY and ALL operators are used with a WHERE or HAVING clause. They enable us to compare a value to any or all values in a subquery or a list...
SQL UNION – Mastering the UNION and UNION ALL Operators
Understanding two extremely useful SQL operators - UNION and UNION ALL. We will understand their syntax, when and why to use them, and of course...
SQL Self Join – The Intricacies of SQL Self Join
Dive deep into one of the most important aspects of SQL, 'The Self Join'. If you're looking to take your SQL skills up a notch, understanding and...
SQL HAVING – A Deep Dive into the SQL HAVING Clause
Deep Dive into a commonly misunderstood but fundamentally powerful aspect of SQL - the `HAVING` clause. The `HAVING` clause, often seen coupled with...
SQL GROUP BY – A Deep Dive into the ‘GROUP BY’ Clause
Unlock the power of data manipulation and summarization with the SQL 'GROUP BY' clause - your key to efficient and insightful data analysis.
SQL Right Join – A Comprehensive Guide on SQL right Join
SQL Right Join - A Comprehensive Guide on SQL right Join
SQL Left Join – A Comprehensive Guide on SQL Left Join
SQL Left Join - A Comprehensive Guide on SQL Left Join
SQL Joins – A Comprehensive Guide
Deep dive into the world of SQL (Structured Query Language), specifically focusing on a pivotal concept – SQL Joins.
SQL Inner Join – The Ins and Outs of SQL Inner Join
An Inner Join in SQL is a method to combine rows from two or more tables based on a related column
SQL Full Join – A Comprehensive Guide on SQL Full Join
A comprehensive guide to SQL FULL JOIN: the syntax, how it returns every row from both tables with NULLs where there is no match, and worked examples...
SQL BETWEEN – A Comprehensive Guide Understanding the SQL BETWEEN Operator
This post focuses on an extremely handy operator, SQL BETWEEN, which is often overlooked yet can immensely optimize your querying process.
SQL Aliases – The Essential Guide to Enhancing Your SQL Code Readability and Efficiency
Dive into SQL aliases, what they are, why you need them, and how to use them effectively.
SQL IN – SQL IN with Practical Examples
Get a handle on one of its powerful operators, the SQL IN operator and covering everything you need to know about it
SQL Wildcards – A Detailed Exploration
Detailed explanation on different types of wildcards available across SQL Server, MySQL, Oracle, and MS Access.
SQL LIKE – Simplified Guide to understanding the SQL ‘LIKE’ Operator
Deep dive into an essential yet often overlooked operator in the SQL toolkit - the 'LIKE' operator
SQL Update – Mastering SQL Update with Examples
Dive deep into one of the most commonly used SQL commands - UPDATE. It is used to modify existing records in a table and is a crucial part of...
SQL SELECT TOP – Diving Deep into the ‘SELECT TOP’ Clause
SELECT TOP is an essential clause for developers and database administrators, allowing for the efficient and strategic handling of voluminous data
SQL ORDER BY – Unraveling SQL’s ORDER BY Clause
Master SQL ORDER BY to sort query results by one or multiple columns. Learn ascending, descending order, NULL handling, and sorting with expressions.
SQL Null Values – Understanding SQL Null Values with Detailed Examples
Exploring an important, yet often misunderstood concept in SQL: `NULL` values. We'll also include hands-on examples with a sample dataset.
SQL MIN and MAX Functions – Unleashing Your Data’s Extremes
Explore two incredibly valuable aggregate functions: MIN() and MAX().
SQL INSERT INTO – A Comprehensive Guide to master SQL INSERT INTO Statement
The SQL INSERT INTO statement is the command you need for this task, allowing you to add new rows of data into a table
SQL DELETE – A Detailed Overview
Master the SQL DELETE statement with practical examples. Learn to delete single rows, multiple rows, use WHERE conditions, and understand DELETE vs...
SQL Count(), Avg(), Sum() – Unraveling SQL Aggregation Functions Count(), Avg(), Sum()
Deep dive into the wonderful world of SQL (Structured Query Language), focusing on three pivotal functions: COUNT(), AVG(), and SUM().
SQL AND, OR, and NOT – A Deep Dive into the AND, OR, and NOT Operators
SQL AND, OR, and NOT - A Deep Dive into the AND, OR, and NOT Operators
SQL WHERE Clause – A Comprehensive Guide
Exploring SQL WHERE syntax, usage, and some real-life examples to give you a robust understanding of this essential command
SQL Select Statement – An Essential Guide to the SQL Select Statement
SQL `SELECT`statement is a crucial starting point. Deep dive into this fundamental command that brings data out of the shadows and into your view.
SQL Select Distinct – A Comprehensive Guide
Deep dive into one of SQL's fundamental operations - the 'Select Distinct' statement.
Introduction to SQL – A Beginner’s Guide
A beginner-friendly introduction to SQL. Learn what SQL is, how relational databases work, and the fundamental commands for querying and managing...