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. Repost from Uniqtech Medium with permission.
Microsoft Excel is a workbook that contain work sheets just like database contains tables.
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.
What is SQL
1. // List Google companies with fewer than 400 employees. 2. var companies = query.filter(‘name =’, ‘Google’).filter(‘size <’, 400);
Important SQL Keywords
SELECT * FROM table_name
*means all columns.
SELECT * FROM (SELECT "A" AS A, "B" AS B);
ASspecifies the alias. When column names are not reader friendly or long, alias is your friend.
FROM database.CUSTOMERS. It can also be followed by a nested query.
where TABLE_NAME.gender == 'Female'. It works on filtering the rows of data.
Putting it all together SELECT FROM WHERE
query = """ SELECT my_column FROM my_table AS m WHERE m.gender = ‘F’ """
“The SQL WITH clause allows you to give a sub-query block a name (a process also called sub-query refactoring), which can be referenced in several places within the main SQL query.” — Geek for geeks
ORDER BY ASC ORDER BY DESC
LIMIT 1000 LIMIT 25