TASIOMIND.DEV — OPERATIONAL▸▸▸FULL STACK DEVELOPER @ GWQ SERVICEPLUS AG▸▸▸FOUNDER — K8SGPT.AI▸▸▸OPEN SOURCE: ACTIVE▸▸▸DISTRIBUTED SYSTEMS / KUBERNETES / AI▸▸▸RUST + GO + PYTHON▸▸▸FIELD TESTED / STATUS — NOMINAL▸▸▸LOCATION: EUROPE/BERLIN▸▸▸TASIOMIND.DEV — OPERATIONAL▸▸▸FULL STACK DEVELOPER @ GWQ SERVICEPLUS AG▸▸▸FOUNDER — K8SGPT.AI▸▸▸OPEN SOURCE: ACTIVE▸▸▸DISTRIBUTED SYSTEMS / KUBERNETES / AI▸▸▸RUST + GO + PYTHON▸▸▸FIELD TESTED / STATUS — NOMINAL▸▸▸LOCATION: EUROPE/BERLIN▸▸▸
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Referencing data from multiple tables using JOINs

November 25, 2017

JOINs verbinden Daten aus mehreren Tabellen.

Inner Join

Nur passende Zeilen:

code
SELECT m.title, g.name
FROM movies m
JOIN genres g ON g.id = m.genre_id;

Left Join

Alle Zeilen links, auch ohne Match:

code
SELECT m.title, g.name
FROM movies m
LEFT JOIN genres g ON g.id = m.genre_id;

Right Join

Alle Zeilen rechts:

code
SELECT m.title, g.name
FROM movies m
RIGHT JOIN genres g ON g.id = m.genre_id;

Cross Join

Kartesisches Produkt:

code
SELECT a.name, b.name
FROM table_a a
CROSS JOIN table_b b;

Link