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I have three tables:
COLLECTION
PERSON
PERSON_COLLECTION
where PERSON_COLLECTION is a mapping table id|person_id|collection_id
I now want to select all entries in collection and order them by person.name.
Do I have to join the separate tables with the mapping table first and then do a join again on the results?
828
The join is done by the JOIN operator. In the FROM clause, the name of the first table ( product ) is followed by a JOIN keyword then by the name of the second table ( category ). This is then followed by the keyword ON and by the condition for joining the rows from the different tables.
Merging tables by columns. Multiple tables can be merged by columns in SQL using joins. Joins merge two tables based on the specified columns (generally, the primary key of one table and a foreign key of the other).
Many common joins are between two tables related by a foreign key. The most common join restricts foreign key values to be equal to primary key values. The KEY JOIN operator joins two tables based on foreign key relationship.
SELECT
c.*,
p.Name
FROM
Collection c
JOIN Person_Collection pc ON pc.collection_id = c.id
JOIN Person p ON p.id = pc.person_id
ORDER BY p.Name
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