Improving the Performance of SQL Queries
Use this topic to find advice on improving the performance of slow queries.
Add the keyword
EXPLAIN in front of your query. For example:
EXPLAIN SELECT * FROM employees WHERE age > ?;
Scanning an entire table (full table scans) is the slowest way to access data, if you are filtering just a small subset of rows. If your queries are performing full table scans on a map, you can create indexes that contain at least one of the columns that the query is filtering in its
WHERE clause. See CREATE INDEX.