ID106 - The unique null treatment when no explicit unique null treatment is specified


UNIQUE NULLS [NOT] DISTINCT (…)
BigQuery 2025-09-02aaDb2 (LUW) 12.1.2aaDerby 10.17.1.0H2 2.3.232MariaDB 12.0.2MySQL 9.3.0Oracle DB 23.9PostgreSQL 17SQL Server 2022SQLite 3.50.0ID106: nulls distinctID106: nulls not distinct
  1. Doesn’t support null-able columns in unique constraints (T591)

Normative References

The implementation defined item ID106, “The unique null treatment when no explicit unique null treatment is specified” is defined in ISO/IEC 9075-2:2023. It first appeared in 2023. Previously, nulls distinct was the standard behavior.

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