How to Efficiently Select Random Rows in SQLite?

Selecting Random Rows in SQLite

In most SQL databases, random row selection can be achieved using the ORDER BY RAND() function. However, in SQLite, this method is not supported.

Alternative Approach for SQLite

To select random rows in SQLite, a more efficient approach is recommended:

SELECT * FROM table WHERE id IN (SELECT id FROM table ORDER BY RANDOM() LIMIT x)

Improved Performance with Indexed Fields

Utilizing the id field for random ordering in the subquery provides significant performance gains:

• Indexed Field Optimization: SQLite accesses indexed fields much faster, reducing RAM and CPU consumption.
• In-Memory Processing: The subquery only sorts the id field in memory, optimizing performance as the table grows.
• Separate Row Selection: By first randomly ordering the id field and then using it to filter the main query, this method ensures efficient selection of the desired number of rows.

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