Learning SQL is not difficult. However, you need to spend a few hours or a few days to learn the basics. On this site you can find a lot of interesting articles, but you need to know the basics of SQL or T-SQL. If you're new to this site and some articles are too hard for you, stay and learn SQL and T-SQL. I came to the conclusion that the best way of learning are video tutorials. 229 minutes of watching and 5 minutes of reading. Let's get started.
Some information about SQL and T-SQL
SQL (Structured Query Language) is a standard language for storing, manipulating and retrieving data in databases (in a relational database management system (RDBMS)). T-SQL (Transact-SQL) is Microsoft's proprietary extension to the SQL. T-SQL expands on the SQL standard to include many useful things.
Level 1: Learning SQL
In this first section, let's look at the basics of the SQL language.
Level 1.1: Introduction to databases
If you are a beginner, then you should familiarize yourself with several theoretical issues.
Level 1.2: Creating database and creating tables
The first thing you need to do is creating a database and tables.
Level 1.3: Inserting data (INSERT INTO clause)
Another thing you need to learn is inserting data into tables.
Level 1.4: Selecting data (SELECT AND ORDER clause)
Now we can start displaying data stored in the database.
Level 1.5: Filtering data (WHERE clause)
Let us now learn to filter data using the WHERE clause.
Level 1.6: Joins
Did you know that data from several tables can be joined with each other?
Level 1.7: Grouping and aggregation (GROUP BY, HAVING, MIN, MAX, AVG, COUNT, DISTINCT)
It's time for slightly more difficult tasks - data grouping and data aggregation.
Level 1.8: Unions (UNION, UNION ALL, INTERSECT, EXCEPT)
And now I will present a different displaying of data from several tables.
Level 1.9: Subqueries
You can write a SQL query inside another query.
Level 1.10: Useful functions (CASE, ROUND, FLOOR, CEILING, LEFT, SUBSTRNG, RIGHT, CHARINDEX, MONTH, YEAR, DAY)
This lesson is a tiny introduction to T-SQL. You will discover a lot of useful functions: CASE, ROUND, FLOOR, CEILING, LEFT, SUBSTRNG, RIGHT, CHARINDEX, MONTH, YEAR, DAY etc
Level 1.11: Update, Alter, Drop, Delete and Truncate clause
Once you've learned how to insert and display data, it's time to learn about data manipulation methods.
Level 1.12: Views
Some queries are used so often, you can save them as views. The views also fulfill several other functions.
One minute break
You already know SQL !!! Make a coffee and let's start. You'll also get to know T-SQL as soon as possible....
Level 2: Learning T-SQL
These videos look at specific ways the T-SQL language is written.
Level 2.1: Creating a database and tables
If you start learning from this place, first create a database
Level 2.2: Transact-SQL Introduction
It's time to get to know the simplest SQL file extensions available in SQL Server
Level 2.3: Views
One more lesson about the views, this time we delve more deeply.
Level 2.4: Stored Procedures
In this lesson, we see how powerful the T-SQL is with some examples.
Level 2.5: User-Defined Functions
If there are stored procedures, then there must also be functions.
Level 2.6: Cursors
Another very useful extension of SQL is the cursor.
Level 2.7: Triggers
A trigger is procedural code that is automatically executed in response to certain events on a particular table or view in a database.
In this way we have reached the end of this course.