{"id":214,"date":"2015-12-01T22:05:03","date_gmt":"2015-12-01T15:05:03","guid":{"rendered":"http:\/\/www.sqlitetutorial.net\/?page_id=214"},"modified":"2024-10-29T20:14:01","modified_gmt":"2024-10-29T13:14:01","slug":"sqlite-inner-join","status":"publish","type":"page","link":"https:\/\/www.sqlitetutorial.net\/sqlite-inner-join\/","title":{"rendered":"SQLite Inner Join"},"content":{"rendered":"\n

Summary<\/strong>: This tutorial shows you how to use the SQLite inner join clause to query data from multiple tables.<\/p>\n\n\n\n

Introduction to SQLite inner join clause<\/h2>\n\n\n\n

In relational databases, data is often distributed in many related tables. A table is associated with another table using foreign keys<\/a>.<\/p>\n\n\n\n

To query data<\/a> from multiple tables, you use INNER JOIN<\/code> clause. The INNER JOIN<\/code> clause combines columns from correlated tables.<\/p>\n\n\n\n

Suppose you have two tables: A and B.<\/p>\n\n\n\n

A has a1, a2, and f columns. B has b1, b2, and f column. The A table links to the B table using a foreign key column named f.<\/p>\n\n\n\n

The following illustrates the syntax of the inner join clause:<\/p>\n\n\n

SELECT<\/span> a1, a2, b1, b2\nFROM<\/span> A\nINNER<\/span> JOIN<\/span> B on<\/span> B.f = A.f;<\/code><\/span>Code language:<\/span> SQL (Structured Query Language)<\/span> (<\/span>sql<\/span>)<\/span><\/small><\/pre>\n\n\n
For each row in the A table, the INNER JOIN<\/code> clause compares the value of the f column with the value of the f column in the B table. If the value of the f column in the A table equals the value of the f column in the B table, it combines data from a1, a2, b1, b2, columns and includes this row in the result set.<\/p>\n\n\n\n
In other words, the INNER JOIN<\/code> clause returns rows from the A table that have the corresponding row in B table.<\/p>\n\n\n\n
This logic is applied if you join more than 2 tables.<\/p>\n\n\n\n
See the following example.<\/p>\n\n\n\n
\"SQLite<\/figure>\n\n\n\n
Only the rows in the A table: (a1,1), (a3,3) have the corresponding rows in the B table (b1,1), (b2,3) are included in the result set.<\/p>\n\n\n\n
The following diagram illustrates the INNER JOIN<\/code> clause:<\/p>\n\n\n\n
\"SQLite<\/figure>\n\n\n\n
SQLite INNER JOIN examples<\/h2>\n\n\n\n
Let’s take a look at the tracks<\/code> and albums<\/code> tables in the sample database<\/a>. The tracks<\/code> table links to the albums<\/code> table via AlbumId<\/code> column.<\/p>\n\n\n\n
\"\"<\/figure>\n\n\n\n
In the tracks<\/code> table, the AlbumId<\/code> column is a foreign key. And in the albums<\/code> table, the AlbumId<\/code> is the primary key<\/a>.<\/p>\n\n\n\n
To query data from both tracks<\/code> and albums<\/code> tables, you use the following statement:<\/p>\n\n\n
SELECT<\/span>\n\ttrackid,\n\tname<\/span>,\n\ttitle\nFROM<\/span>\n\ttracks\nINNER<\/span> JOIN<\/span> albums ON<\/span> albums.albumid = tracks.albumid;<\/code><\/span>Code language:<\/span> SQL (Structured Query Language)<\/span> (<\/span>sql<\/span>)<\/span><\/small><\/pre>\n\n\n
\"SQLite<\/figure>\n\n\n\n
For each row in the tracks table, SQLite uses the value in the albumid<\/code> column of the tracks<\/code> table to compare with the value in the albumid<\/code> of the albums<\/code> table. If SQLite finds a match, it combines data of rows in both tables in the result set.<\/p>\n\n\n\n
You can include the AlbumId<\/code> columns from both tables in the final result set to see the effect.<\/p>\n\n\n
SELECT<\/span>\n    trackid,\n    name<\/span>,\n    tracks.albumid AS<\/span> album_id_tracks,\n    albums.albumid AS<\/span> album_id_albums,\n    title\nFROM<\/span>\n    tracks\n    INNER<\/span> JOIN<\/span> albums ON<\/span> albums.albumid = tracks.albumid;<\/code><\/span>Code language:<\/span> SQL (Structured Query Language)<\/span> (<\/span>sql<\/span>)<\/span><\/small><\/pre>\n\n\n
\"SQLite<\/figure>\n\n\n\n
SQLite inner join – 3 tables example<\/h3>\n\n\n\n
See the following tables:tracks<\/code> albums<\/code> and artists<\/code><\/p>\n\n\n\n
\"\"<\/figure>\n\n\n\n
One track belongs to one album and one album has many tracks. The tracks<\/code> table associated with the albums<\/code> table via albumid<\/code> column.<\/p>\n\n\n\n
One album belongs to one artist and one artist has one or many albums. The albums<\/code> table links to the artists<\/code> table via artistid<\/code> column.<\/p>\n\n\n\n
To query data from these tables, you need to use two inner join clauses in the SELECT<\/a><\/code> statement as follows:<\/p>\n\n\n
SELECT<\/span>\n    trackid,\n    tracks.name AS<\/span> track,\n    albums.title AS<\/span> album,\n    artists.name AS<\/span> artist\nFROM<\/span>\n    tracks\n    INNER<\/span> JOIN<\/span> albums ON<\/span> albums.albumid = tracks.albumid\n    INNER<\/span> JOIN<\/span> artists ON<\/span> artists.artistid = albums.artistid;<\/code><\/span>Code language:<\/span> SQL (Structured Query Language)<\/span> (<\/span>sql<\/span>)<\/span><\/small><\/pre>\n\n\n
\"SQLite<\/figure>\n\n\n\n
You can use a WHERE clause<\/a> to get the tracks and albums of the artist with id 10 as the following statement:<\/p>\n\n\n
SELECT<\/span>\n\ttrackid,\n\ttracks.name AS<\/span> Track,\n\talbums.title AS<\/span> Album,\n\tartists.name AS<\/span> Artist\nFROM<\/span>\n\ttracks\nINNER<\/span> JOIN<\/span> albums ON<\/span> albums.albumid = tracks.albumid\nINNER<\/span> JOIN<\/span> artists ON<\/span> artists.artistid = albums.artistid\nWHERE<\/span>\n\tartists.artistid = 10<\/span>;<\/code><\/span>Code language:<\/span> SQL (Structured Query Language)<\/span> (<\/span>sql<\/span>)<\/span><\/small><\/pre>\n\n\n
\"SQLite<\/figure>\n\n\n\n
In this tutorial, you have learned how to use SQLite INNER JOIN<\/code> clause to query data from multiple tables.<\/p>\n
\n\t
\n\t\t
Was this tutorial helpful ?<\/div>\n\t\t
\n\t\t\t\n\t\t\t\t\n\t\t\t\t\t<\/path>\n\t\t\t\t<\/svg>\n\t\t\t\t Yes <\/span>\n\t\t\t<\/button>\n\n\t\t\t\n\t\t\t\t\n\t\t\t\t\t<\/path>\n\t\t\t\t<\/svg>\n\t\t\t\t No <\/span>\n\t\t\t<\/button>\n\t\t<\/div>\n\t<\/header>\n\n\t
\n\t\t
\n\t\t\t
<\/div>\n\t\t\t\n\t\t\t
Try It<\/a><\/p>\n\n\n\n
Try It<\/a><\/p>\n\n\n\n
Try It<\/a><\/p>\n\n\n\n
Try It<\/a><\/p>\n\n\n\n