For an instructor lead, in-depth look at learning SQL click below.
Welcome to world of SQL! SQL, short for Structured Query Language, is a database tool used to communicate with and manipulate databases. Regardless of your background, understanding SQL can be extremely beneficial and can give you a boost in your career. This tutorial is designed to walk beginners through basic SQL commands and conventions. Prepare to start querying!
Getting Started
The first thing to learn in SQL is how to retrieve data, the most basic command to do this is SELECT. Here is its basic syntax:
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SELECT column_name(s) FROM table_name; |
This command will select data from a database. You replace ‘column_name(s)’ with the name of the column you want to get data from, and ‘table_name’ with the name of the table where the column resides.
For example, let’s consider we have a table named ‘Students’. This table has two columns, ‘name’ and ‘age’. If we want to get all the names from this table, we would use the following command:
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SELECT name FROM Students; |
Filtering Records
SQL also provides a way to filter records, which can be achieved using the WHERE clause. Here’s a typical structure:
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SELECT column_name(s) FROM table_name WHERE condition; |
For example, if we want to get a list of all students who are above 18 years of age, we’ll use the WHERE clause as follows:
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SELECT name FROM Students WHERE age > 18; |
Combining conditions
You can specify multiple conditions in a WHERE clause to narrow down your data using AND, OR, and NOT. Let’s illustrate this with an example:
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SELECT name FROM Students WHERE age > 18 AND age < 22; |
This statement will give us the names of students aged between 19 and 21.
Conclusion
That’s a wrap on our SQL 101 tutorial! We’ve just scratched the surface here; SQL is a power-packed language with numerous functionalities to learn. Persistence and practice are key when learning SQL, or any new language for that matter. Good luck exploring further!