How to optimize a SELECT ... WHERE id IN (...) query with a very large list of values?

When using a query with a very large list of values in WHERE id IN (...), there are performance issues and query length limitations. To optimize such a query, you can:

• Use a temporary table or table variable: Instead of passing a large list of values directly, load these values into a temporary table and perform a JOIN with it.

• Split the query into smaller ones: Divide the large list into parts and execute multiple queries with smaller lists.

• Use parameterized queries with arrays: If the database supports it, pass the list as an array or use constructs like ANY.

• Use EXISTS with a subquery: Sometimes, a subquery with EXISTS works more efficiently.

Example with a temporary table in PostgreSQL:

CREATE TEMP TABLE temp_ids (id INT);

-- Insert values
INSERT INTO temp_ids VALUES (1), (2), (3), ...;

-- Query with JOIN
SELECT * FROM main_table mt
JOIN temp_ids ti ON mt.id = ti.id;

This reduces the load on the parser and query optimizer and improves performance.