Learn SQL — It’s on every job listing — Part 1

SQL is not obsolete. You can now build Machine Learning models with SQL, query real time or big data with SQL. It is true if you look around you will find plenty of job postings with SQL as a desired skill, even from FANG companies (Facebook, Apple, Netflix, Google). Uniqtech writes technical tutorials for coding bootcamp graduates, free lancers, self-study, MOOC students who are in the realm of data science, software engineering, machine learning and deep learning. Read our disclaimer here. This disclaimer applies to our entire site. Please take our words with a grain of salt. They are not considered professional advice nor are they considered professional opinions.

Table of contents: part 1 — intro to SQL (this article), part 2 create read update delete with SQL.

Microsoft Excel is a workbook that contain work sheets just like database contains tables.

Each table can be queried separately. To query tables, jointly, we will need to use join statements and keys to look up the corresponding data.

Each table row should have a unique ID, known as the primary ID. It can also have a foreign key (FK) which associates the row, aka record, with a unique primary ID of another table.

For example each e-commerce transaction has an unique ID, which can be generated with the timestamp of when the transaction happened. Each transaction ID can have a FK such as customer ID, which uniquely identifies the customer that made the transaction. His or…