SQL

Well organized and easy to follow SQL examples. Many practical use cases covering most useful operation related to SQL, MySQL, Oracle. Learn how to use SQL to query and manipulate data. SQL selects, joins, delete, update and much more.

SQL/MySQL How to query 3 tables with or wihtout a join

You can query more than 2 tables with SQL. Below

John D K

Sep 13, 2018

2 min read

JIRA how to format code python, SQL, Java

You have two options of formatting code in JIRA: using

John D K

Aug 16, 2018

1 min read

MySQL create, alter and drop table, DB

In previous posts we saw some DML(Data Manipulation Language)

John D K

Mar 22, 2018

1 min read

MySQL coalesce, exists, union and having example

Working with SQL requires formatting and filtering of data which

John D K

Mar 21, 2018

2 min read

MySQL update, insert, delete examples

In this post we will cover the rest of the

John D K

Mar 15, 2018

1 min read

SQL select aggregate functions examples

In this post we will cover most used SQL select

John D K

Mar 14, 2018

1 min read

SQL select examples

This is part of tutorial learning SQL from beginners in

John D K

Mar 13, 2018

1 min read

mysql join simple example for beginners

SQL join are explained by Venn diagrams. Venn diagrams are

John D K

Feb 27, 2018

3 min read

Oracle count null and not null values in column

In this article we will post two ways of counting

John D K

Feb 23, 2018

1 min read

MySQL 5.7 show table columns 3 ways

1 Show MySQL table columns by describe The simplest and

John D K

Feb 22, 2018

1 min read

MySQL 5.7 alter table add column

Adding new table is most common DDL operation that I'm

John D K

Feb 22, 2018

1 min read

MySQL update embedded select

Simple example of update using nested query or in other

John D K

Feb 6, 2018

1 min read

MySQL 8 embedded update over several tables

MySQL update one table embedded select UPDATE table1 t1, ( SELECT

John D K

Dec 21, 2017

1 min read

Nice article about 10 SQL optimisations: MySQL, Oracle, SQL Server, DB2, PostgreSQL

Recently I found a very nice article explaining in great

John D K

Oct 2, 2017

1 min read

Full back up, update and reinstall of MySQL Ubuntu 16

Back up MySQL manually or by script Manual back up

John D K

Sep 2, 2017

2 min read

Oracle, MySQL - select max and return multiple values

A common problems in SQL are to find the data

John D K

Aug 31, 2017

5 min read

Oracle indexes - create, rebuild, select, drop

Select all indexes by status Check indexes by status by

John D K

Aug 30, 2017

3 min read

SQL concatenate examples

Concatenation basics concatenation functions: Oracle - concat MySQL - concat

John D K

Aug 29, 2017

1 min read

Frequent SQL commands DML and DDL

Frequent SQL commands part 2 Data manipulatiuon language DML --

John D K

Jul 6, 2017

1 min read

Frequent SQL commands select

Frequent SQL commands This is my SQL cheat-sheet for MYSQL.

John D K

Jul 5, 2017

3 min read