Зміст курсу

SQL Tutorial for Beginners

1. Database & Introduction to Syntax

Meet the SQL Select the Songs!SQL Select Column SQL Distinct SQL Where Challenge Where SQL And, Or, Not

2. SQL Aggregate Functions

SQL Min and Max Challenge Min and Max SQL Count, Sum, Avg Challenge Count

3. Filtering Statements

SQL Null SQL Like Challenge Like SQL Between SQL Order By Challenge Order By SQL Group By Challenge Group By SQL Top and Limit SQL Aliases SQL Having Challenge Having SQL Comments

SQL Distinct

Distinct is a keyword used with SELECT to return only unique values. Usually, you want to get all unique values, but there are duplicate values stored in the tables.

Check the difference: in our table, there are 18 records at all, and each record has a singer. You'll retrieve the 18 singers with the next query:


              12
            
SELECT singer
FROM songs

But some singers, for example, AC/DC, occur multiple times. To retrieve the unique singers, use the DISTINCT keyword before the singer column:


              12
            
SELECT DISTINCT singer
FROM songs

Now there are no repeated values, so you can see that the total number of unique singers is 10.

Завдання

Find all unique title values in songs.

Завдання

Find all unique title values in songs.

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Все було зрозуміло?

Секція 1. Розділ 4

SQL Distinct

Distinct is a keyword used with SELECT to return only unique values. Usually, you want to get all unique values, but there are duplicate values stored in the tables.

Check the difference: in our table, there are 18 records at all, and each record has a singer. You'll retrieve the 18 singers with the next query:


              12
            
SELECT singer
FROM songs

But some singers, for example, AC/DC, occur multiple times. To retrieve the unique singers, use the DISTINCT keyword before the singer column:


              12
            
SELECT DISTINCT singer
FROM songs

Now there are no repeated values, so you can see that the total number of unique singers is 10.

Завдання

Find all unique title values in songs.

Завдання

Find all unique title values in songs.

Все було зрозуміло?

Секція 1. Розділ 4

SQL Distinct

Distinct is a keyword used with SELECT to return only unique values. Usually, you want to get all unique values, but there are duplicate values stored in the tables.

Check the difference: in our table, there are 18 records at all, and each record has a singer. You'll retrieve the 18 singers with the next query:


              12
            
SELECT singer
FROM songs

But some singers, for example, AC/DC, occur multiple times. To retrieve the unique singers, use the DISTINCT keyword before the singer column:


              12
            
SELECT DISTINCT singer
FROM songs

Now there are no repeated values, so you can see that the total number of unique singers is 10.

Завдання

Find all unique title values in songs.

Завдання

Find all unique title values in songs.

Все було зрозуміло?

Distinct is a keyword used with SELECT to return only unique values. Usually, you want to get all unique values, but there are duplicate values stored in the tables.

Check the difference: in our table, there are 18 records at all, and each record has a singer. You'll retrieve the 18 singers with the next query:


              12
            
SELECT singer
FROM songs

But some singers, for example, AC/DC, occur multiple times. To retrieve the unique singers, use the DISTINCT keyword before the singer column:


              12
            
SELECT DISTINCT singer
FROM songs

Now there are no repeated values, so you can see that the total number of unique singers is 10.

Завдання

Find all unique title values in songs.

Секція 1. Розділ 4