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Improving the Performance of SQL Queries

Use this topic to find advice on improving the performance of slow queries.

Displaying the Execution Plan

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.