ISO/IEC 9075-2:2016 Information Technology — Database Languages — SQL — Part 2

(2016). ISO/IEC 9075-2:2016 Information Technology — Database Languages — SQL — Part 2: Foundation (SQL/Foundation). ISO.

Type

Standard

Intellectual base

Reference work

Year

2016

Link

https://www.iso.org/standard/63556.html

Cited from

mathematics

Cited by

2 citations across 2 artifacts.

Each citation links to the sentence it supports in the citing article.

Primes

• Union
  • In databases it is the SQL UNION operator, which merges the result sets of two queries into one (with UNION deduplicating and UNION ALL keeping every row — exactly the set-versus-multiset distinction)

    This sourcePart 2 (Foundation) specifies SQL's query expressions including the UNION operator (deduplicating) and UNION ALL (multiset, duplicates kept) — the set-versus-multiset distinction made operational.

Mechanisms

• Set-Difference Query
  • The complement is computed as a set difference — in SQL, `SELECT customer_id FROM active_customers EXCEPT SELECT customer_id FROM spring_buyers`.

    This sourceDefines SQL EXCEPT as the set difference of its left and right query blocks, matching the shown active-customer-minus-spring-buyer query.

Verification

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