Can I create a column index only for null, or just not null?

When creating index for a column creates a new table for the indexes and the database increases. I need to index only values with null data. Search for 'where column = null'. Thus, the database would be slightly less than if content value is null.
April 19th 20 at 12:03
2 answers
April 19th 20 at 12:05
Solution
it does not happen, do the two tables then
April 19th 20 at 12:07
When creating index for a column creates a new table for indexes

It is not a table.

Search for 'where column = null'.

For this condition no need any index or even data. By definition, an empty sample on the stage of the parser.

When talking about where column is null - it happens in principle, is called the partial index (partial index). But mysql is still not able.

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