Optimize SQLite Queries for Millions of Rows

To improve query performance when querying large amounts of data in SQLite, the following methods can be used:

1. Using indexes: Creating indexes on columns that are frequently queried can significantly improve query performance. Indexes can be created on columns of a table using the CREATE INDEX statement.
2. Employing LIMIT and OFFSET: By utilizing the LIMIT and OFFSET clauses, you can restrict the size of the result set returned and process large amounts of data in batches. This helps prevent performance degradation from returning a massive amount of data in one query.
3. Choose appropriate data types: When creating tables, selecting the right data types can improve query performance. Avoid unnecessary data conversion operations in queries.
4. Use the EXPLAIN statement: Analyze the query plan using the EXPLAIN statement to see if indexes are being used, if full table scans exist, and to optimize query performance.
5. Avoid using SELECT: Instead of using SELECT to query all columns, only select the columns that are needed to reduce the amount of returned data.
6. Using subqueries and joins: utilizing subqueries and joins in complex queries can optimize query performance and avoid multiple database calls.

Here are some methods to improve SQLite query performance. Select the appropriate method based on the specific situation to optimize query performance.