ObsidianVault/SS2026/Datenbanken und Informationssysteme/4. SQL/DQL Data Query Language SQL.md

SELECT

SELECT MatrNr, Name, Semester from Student

Spalte umbenennen SELECT MatrNr AS InsassenNr from Student

Keine Duplikate SELECT DISTINCT Semester AS Jahrgänge from Student

WHERE

SELECT * from Student WHERE Semester = 2
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SELECT * from Student s WHERE s.Semester = 2 AND s.Name='Byleth' 

Anatomie einer WHERE Klausel

Vergleichsoperatoren: <,>,=,<=,>=,<> BETWEEN LIKE IS NULL / IS NOT NULL AND, OR, NOT +,-,*,/ IN, NOT IN, \theta ANY, \theta ALL, EXISTS mit \theta = Vergleichsoperator