IB Computer Science Topic A3.3.2 Constructing Queries Between Two Tables in SQL Revision Notes (SL/HL)

IB Computer Science Topic A3.3.2 Constructing Queries Between Two Tables in SQL Revision Notes (SL/HL) | RevisionDojo

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Constructing Queries Between Two Tables in SQL

Understanding Joins in SQL

Inner Join: Returns rows with matching values in both tables.
Left Join: Returns all rows from the left table and matching rows from the right table. If no match, NULLs are returned.
Right Join: Returns all rows from the right table and matching rows from the left table. If no match, NULLs are returned.

Note

The JOIN clause is essential for combining data from multiple tables, allowing you to create comprehensive queries that leverage relationships between entities.

Basic Syntax of a Join

SELECT table1.column1, table2.column2

FROM table1

JOIN table2 ON table1.common_column = table2.common_column;

Example

SELECT Item.ItemID, Item.ItemDesc, Artist.ArtistName

FROM Item

JOIN Artist ON Item.ArtistID = Artist.ArtistID;

WHERE item.ItemCost BETWEEN 100 AND 300;

Tip

Use BETWEEN for inclusive range queries, and LIKE with % for flexible pattern matching.

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Note

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Excepteur sint occaecat cupidatat non proident

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Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

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Constructing Queries Between Two Tables in SQL

Understanding Joins in SQL

Inner Join: Returns rows with matching values in both tables.
Left Join: Returns all rows from the left table and matching rows from the right table. If no match, NULLs are returned.
Right Join: Returns all rows from the right table and matching rows from the left table. If no match, NULLs are returned.

Note

The JOIN clause is essential for combining data from multiple tables, allowing you to create comprehensive queries that leverage relationships between entities.

Basic Syntax of a Join

SELECT table1.column1, table2.column2

FROM table1

JOIN table2 ON table1.common_column = table2.common_column;

Example

SELECT Item.ItemID, Item.ItemDesc, Artist.ArtistName

FROM Item

JOIN Artist ON Item.ArtistID = Artist.ArtistID;

WHERE item.ItemCost BETWEEN 100 AND 300;

Tip

Use BETWEEN for inclusive range queries, and LIKE with % for flexible pattern matching.

Definition

Paywall

(on a website) an arrangement whereby access is restricted to users who have paid to subscribe to the site.

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Note

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam quis nostrud exercitation.

Excepteur sint occaecat cupidatat non proident

Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

A1 Computer fundamentals4 subtopics

A2 Networks4 subtopics

A3 Databases4 subtopics

A4 Machine learning4 subtopics

B1 Computational thinking1 subtopic

B2 Programming5 subtopics

B3 Object-oriented programming2 subtopics

B4 Abstract data types (HL only)1 subtopic

IB Computer Science Topic A3.3.2: Constructing Queries Between Two Tables in SQL Notes

A1 Computer fundamentals4 subtopics

A2 Networks4 subtopics

A3 Databases4 subtopics

A4 Machine learning4 subtopics

B1 Computational thinking1 subtopic

B2 Programming5 subtopics

B3 Object-oriented programming2 subtopics

B4 Abstract data types (HL only)1 subtopic

Constructing Queries Between Two Tables in SQL

Understanding Joins in SQL

Basic Syntax of a Join

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Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

Constructing Queries Between Two Tables in SQL

Understanding Joins in SQL

Basic Syntax of a Join

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account