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Data Manipulation using SQL
course content

Course Content

Data Manipulation using SQL

Data Manipulation using SQL

1. Database and Nested Queries
DatabaseSQL In StatementChallenge In StatementSQL Exists Statement
2. SQL Joining Tables
SQL Inner JoinSQL JoinsSQL Left & Right JoinSQL Full Outer JoinSQL Union
3. SQL Tasks
Challenge: Albums with Two SongsChallenge: the Biggest AlbumChallenge: Rating of SingersChallenge: DecadesChallenge: Two SingersChallenge: Solo vs BandsChallenge: Solo AlbumsChallenge: Singers Stats

bookSQL Union

UNION is an operator that concatenates results of different SQL queries:


              
1234567

            
--do not run this query
SELECT columns FROM table1
UNION
SELECT columns FROM table2
UNION
...
SELECT columns FROM tableN
copy

There is also an operator UNION ALL, and the difference is that UNION returns distinct values, unlike UNION ALL.

Requirements for using UNION operators:

  • number of columns in SELECT should be the same
  • data types and order of columns should be the same

Task

You want to get some info about songs from three decades: 1970s, 1980s, and 1990s. Find the prices of the cheapest and the most expensive songs for each decade in separate queries. You're free to use JOIN, BETWEEN, or any other operators, but you should do three separate queries and concatenate them with UNION.

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Section 2. Chapter 5
toggle bottom row

bookSQL Union

UNION is an operator that concatenates results of different SQL queries:


              
1234567

            
--do not run this query
SELECT columns FROM table1
UNION
SELECT columns FROM table2
UNION
...
SELECT columns FROM tableN
copy

There is also an operator UNION ALL, and the difference is that UNION returns distinct values, unlike UNION ALL.

Requirements for using UNION operators:

  • number of columns in SELECT should be the same
  • data types and order of columns should be the same

Task

You want to get some info about songs from three decades: 1970s, 1980s, and 1990s. Find the prices of the cheapest and the most expensive songs for each decade in separate queries. You're free to use JOIN, BETWEEN, or any other operators, but you should do three separate queries and concatenate them with UNION.

Switch to desktopSwitch to desktop for real-world practiceContinue from where you are using one of the options below
Everything was clear?

How can we improve it?

Thanks for your feedback!

Section 2. Chapter 5
toggle bottom row

bookSQL Union

UNION is an operator that concatenates results of different SQL queries:


              
1234567

            
--do not run this query
SELECT columns FROM table1
UNION
SELECT columns FROM table2
UNION
...
SELECT columns FROM tableN
copy

There is also an operator UNION ALL, and the difference is that UNION returns distinct values, unlike UNION ALL.

Requirements for using UNION operators:

  • number of columns in SELECT should be the same
  • data types and order of columns should be the same

Task

You want to get some info about songs from three decades: 1970s, 1980s, and 1990s. Find the prices of the cheapest and the most expensive songs for each decade in separate queries. You're free to use JOIN, BETWEEN, or any other operators, but you should do three separate queries and concatenate them with UNION.

Switch to desktopSwitch to desktop for real-world practiceContinue from where you are using one of the options below
Everything was clear?

How can we improve it?

Thanks for your feedback!

UNION is an operator that concatenates results of different SQL queries:


              
1234567

            
--do not run this query
SELECT columns FROM table1
UNION
SELECT columns FROM table2
UNION
...
SELECT columns FROM tableN
copy

There is also an operator UNION ALL, and the difference is that UNION returns distinct values, unlike UNION ALL.

Requirements for using UNION operators:

  • number of columns in SELECT should be the same
  • data types and order of columns should be the same

Task

You want to get some info about songs from three decades: 1970s, 1980s, and 1990s. Find the prices of the cheapest and the most expensive songs for each decade in separate queries. You're free to use JOIN, BETWEEN, or any other operators, but you should do three separate queries and concatenate them with UNION.

Switch to desktopSwitch to desktop for real-world practiceContinue from where you are using one of the options below
Section 2. Chapter 5
Switch to desktopSwitch to desktop for real-world practiceContinue from where you are using one of the options below
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