Senior LevelSQL & MySQL
How do Multi-Valued Indexes index JSON arrays in MySQL 8.0?
❓ Interview Prompt: Explain MySQL 8.0 Multi-Valued Indexes, indexing JSON array elements, `MEMBER OF()`, `JSON_CONTAINS()`, and B-Tree array pointers.
Standard B-Tree indexes map 1 row to 1 index key. MySQL 8.0 Multi-Valued Indexes allow a single row containing a JSON array to create multiple B-Tree index pointers:
Usage:
Constructed over JSON arrays (e.g. 'CAST(data->'$.tags' AS UNSIGNED ARRAY)').
•
Queries using 'MEMBER OF()', 'JSON_CONTAINS()', or 'JSON_OVERLAPS()' use the Multi-Valued B-Tree index directly!
Code Implementation Example
sql
-- Creating a Multi-Valued Index on JSON tags array
CREATE TABLE articles (
id INT PRIMARY KEY,
tags JSON,
INDEX idx_tags ((CAST(tags AS UNSIGNED ARRAY)))
);
-- Query uses Multi-Valued B-Tree Index!
EXPLAIN SELECT * FROM articles WHERE 42 MEMBER OF(tags);💡Indexing JSON arrays using a MySQL 8 Multi-Valued Index.
🎯 Interview Key Takeaway
Use Multi-Valued Indexes in MySQL 8 to accelerate queries searching inside JSON array attributes.
#MySQL 8#Multi-Valued Index#JSON#Indexes#Senior
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