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Mastering Apache Cassandra 3.x - Third Edition
book

Mastering Apache Cassandra 3.x - Third Edition

by Aaron Ploetz, Tejaswi Malepati
October 2018
Beginner to intermediate content levelBeginner to intermediate
348 pages
10h
English
Packt Publishing
Content preview from Mastering Apache Cassandra 3.x - Third Edition

DISTINCT

CQL has a construct that intrinsically removes duplicate partition key entries from a result set, using the DISTINCT keyword. It works in much the same way as its SQL counterpart:

SELECT DISTINCT last_name FROM customer; last_name-----------       Tam Washburne(2 rows)

The main difference of DISTINCT in CQL is that it only operates on partition keys and static columns.

The only time in which DISTINCT is useful is when running an unbound query. This can appear to run efficiently in small numbers (fewer than 100). Do remember that it still has to reach out to all the nodes in the cluster.
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Publisher Resources

ISBN: 9781789131499Supplemental Content