How to Solve ORA-01795: Maximum Number of Expressions in a List?

ORA-01795: Overcoming the Limit of Expressions in a List

When attempting to query a database with multiple values using an IN clause, you may encounter the "ORA-01795: maximum number of expressions in a list is 1000 error." This error arises when the number of values in the IN clause exceeds the limit of 1000.

Workaround: Divide and Conquer

To circumvent this restriction, it is necessary to divide the list of values into multiple smaller groups. The following workaround can be implemented:

• Divide the list of values into chunks of 999 expressions or less.
• Use multiple IN clauses to query the database for each chunk of values.

For example, consider the query:

SELECT field1, field2, field3
FROM table1
WHERE name IN
(
'value1',
'value2',
...
'value10000+'
);

Can be rewritten using multiple IN clauses as follows:

SELECT field1, field2, field3
FROM table1
WHERE  name IN ('value1', 'value2', ..., 'value999')
    OR name IN ('value1000', ..., 'value1999')
    OR ...;

By dividing the list of values into smaller chunks, the query can be executed without encountering the ORA-01795 error. This workaround provides a straightforward solution for handling large lists of values in database queries.

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