Often it's not enough to check for only one condition. What if we want to check if multiple conditions hold at the same time? Or at least one of them?

Conditions in SQL can be combined by using `AND` and `OR` statements within `WHERE` block. `AND` checks if **all** the conditions hold while `OR` checks if **at least one** of the conditions holds. For example, we can combine conditions from the two previous chapters: filter for hybrid cars with mileage less than 5000 miles.

SELECT *
FROM audi_cars
WHERE fueltype = 'Hybrid' AND mileage < 5000

Also, we can extract only either cars with Automatic transmission either with an engine size less than 3 by using `OR` statement.

SELECT *
FROM audi_cars
WHERE transmission = 'Automatic' OR enginesize < 3

SQL is a domain-specific programming language widely used by data scientists, analysts, etc for manipulating and extracting necessary data. Nowadays, SQL is a must-have point in the CV for every potential analyst, data scientist. In this course, you will be introduced to the very basics of SQL.

In this section, you will be introduced to the very basics of SQL: extracting one or multiple columns from a database.

In this section, you will learn how to filter observations so only necessary rows will be extracted.

In this section, you will learn about the usage of different aggregating functions for your table, such as minimum, maximum, average... 

In this section, you will learn how to sort your table, even having filters and aggregate functions applied to a table.

In this section, you will learn about grouping observations and usage of this principle.

This chapter is designed for users who have completed the previous sections and want to consolidate knowledge.

Combining conditions

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