Does MySQL ignore null values on unique constraints?

Does MySQL ignore null values on unique constraints?

mysql database unique-constraint

database

Can I add a UNIQUE constraint to a PostgreSQL table, after it's already created?

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database

UNIQUE constraint failed: sqlite database : android

java android database sqlite unique-constraint

database

Unique (multiple columns) and null in one column

mysql sql database unique-constraint

database

How to drop a unique constraint from table column?

sql database sql-server-2005 unique-constraint non-clustered-index

database

duplicate null value violation on UNIQUE KEY constraint in Mssql

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database

Are unique constraints on the DB necessary?

database database-design constraints unique-constraint

database

Django custom unique together constraint

database django validation postgresql unique-constraint

database

Is it possible to create a Unique (Index) constraint across multiple tables?

mysql sql database unique-constraint

database

Conditional unique constraint in oracle

database oracle constraints unique-constraint

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In Django, how to find rows which would violate a unique together constraint?

python django database migration unique-constraint

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