user4757174 user4757174 - 26 days ago 13
MySQL Question

Add column to existing multi-column index

In my table I have a multi-column index for the columns (name,folder)

I recently added a new column called date and I want to put an index into it, but I want to put it into the existing multi-column index

When I do

Alter table books add index theindex (date);

I get
Duplicate key name 'theindex'


How do I add another column to an index without creating a new key?

Answer

Just change the syntax to the below way to add new columns to the index:

ALTER table `books` DROP INDEX theindex;
ALTER table `books` ADD INDEX theindex (`date`, `time`);
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