Aanwezigheid en afwezigheid

De queryprestaties verbeteren in SQL Server

Dean Smith

Founder, Atamai Analytics

Venn-diagram – aanwezigheid

Data die in beide tabellen staat.

Venn-diagram Aanwezigheid

Data in de linkertabel die ontbreekt in de rechtertabel.

Venn-diagram Afwezigheid

Database Customers Orders

SELECT CustomerID
FROM Customers






SELECT CustomerID
FROM Orders;

SELECT CustomerID
FROM Customers


INTERSECT


SELECT CustomerID
FROM Orders;

SELECT CustomerID
FROM Customers






SELECT CustomerID
FROM Orders;

SELECT CustomerID
FROM Customers


EXCEPT


SELECT CustomerID
FROM Orders;

CustomerID
FISSA
PARIS

Voordelen

Nadelen

De queryprestaties verbeteren in SQL Server