What is the difference between MySQL PRIMARY KEY and UNIQUE constraints?

The following table will provide us the difference between PRIMARY KEY and UNIQUE constraints-

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Primary Key	Unique constraint
1. A table can only create one primary key.	1. Multiple UNIQUE constraints can be added to a table.
#2. The primary key creates a clustered index by default.	2. UNIQUE constraints create non-clustered indexes by default.
#3. We cannot insert null values ​​in columns defined as PRIMARY KEY.	3. We can insert null values ​​in columns with UNIQUE constraints.

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