[Solved] Select distinct substrings that are in a comma separated string | MySql

How to optimize this SQL query?

In case you have your own slow SQL query, you can optimize it automatically here.

For the query above, the following recommendations will be helpful as part of the SQL tuning process.
You'll find 3 sections below:

  1. Description of the steps you can take to speed up the query.
  2. The optimal indexes for this query, which you can copy and create in your database.
  3. An automatically re-written query you can copy and execute in your database.
The optimization process and recommendations:
  1. Index Function Calls Using Generated Columns (modified query below): When a function is used directly on an indexed column, the database's optimizer won’t be able to use the index to optimize the search. Creating and indexing a generated column (supported in MySQL 5.7) will allow MySQL to optimize the search.
The optimized query:
SELECT
        tablename.id,
        SUBSTRING_INDEX(SUBSTRING_INDEX(tablename.name,
        ',',
        numbers.n),
        ',',
        -1) name 
    FROM
        numbers 
    INNER JOIN
        tablename 
            ON tablename.char_length_name - tablename.char_length_replace_name >= numbers.n - 1 
    ORDER BY
        tablename.id,
        n

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* original question posted on StackOverflow here.