MySQL 8 Administrator???s Guide

Handling NULL in partitioning

There is nothing specific to MySQL 8 that disallows NULL in partitioning as a column value, partitioning expression, or the value from the user-defined expression. Even if NULL is permitted as a value ,the value returned from the expression must be an integer and so MySQL 8 has implementation for partitioning such that it treats NULL as less than any non-NULL value as done in the ORDER BY clause.

Behavior for NULL handling varies among different types of partitioning:

• Handling NULL in RANGE partitioning: If a NULL value contained in the column is inserted, the row will be inserted in the lowest partition specified in range
• Handling NULL with LIST partitioning: If the table has a partitioning definition with ...