Is there a workaround for ORA-01795: maximum number of expressions in a list is 1000 error?

Workarounds and Optimizations

Using Multiple "IN" Clauses

When temporary tables aren't your flavor of the day, consider breaking your list into multiple "IN" clauses. Connect each subset using OR to stay in Oracle's good graces.

SELECT *
FROM your_table
WHERE column_name IN (/* "Here's Johnny" with first 1000 items */)
OR column_name IN (/* "I'm back!" with second 1000 items */) 
OR ...
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Tuples, Table Types & CARDINALITY Hint

Wield tuples in an "IN" clause or define a custom table type, because Oracle plays nice with these:

-- Tuples, the double agent of the SQL world
SELECT *
FROM your_table
WHERE (col1, col2) IN (SELECT col1, col2 FROM large_data_set)


Use a table type for larger IN lists:

-- Custom table type, tailored to fit
CREATE TYPE number_table IS TABLE OF NUMBER;

-- Deploying the table function, Like a boss
SELECT *
FROM your_table
JOIN TABLE(CAST(:your_typ_var AS number_table)) tmp ON your_table.column = tmp.column_value
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Boost your code with the CARDINALITY hint:

SELECT /*+ CARDINALITY(tl 10000) */ *
FROM your_table jt
JOIN TABLE(SYS.ODCINUMBERLIST(...)) tl ON jt.column_name = tl.column_value
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The UNION ALL Approach

UNION ALL concatenates individual queries for expedient results:

-- Multiple queries? No sweat!
SELECT * FROM your_table WHERE column_name IN (/* first 1000 values */) 
UNION ALL
SELECT * FROM your_table WHERE column_name IN (/* second 1000 values */)
-- And so on...
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Visualization

Think of the ORA-01795 error workaround as a free-ride bus service for over a thousand passengers:

🚌: "Beep Beep! Sorry, limit is 1000 passengers at a time!"

The solution is subsequent journeys for all passengers:

SELECT * FROM passengers WHERE id IN (/* first 1000 IDs */)
UNION ALL
SELECT * FROM passengers WHERE id IN (/* next 1000 IDs */)
-- Repeat until all passengers have been served 🚶‍♀️🚶‍♂️


This avoids crowding the bus, ensuring each journey (query) carries no more than 1000 expressions, effectively bypassing the ORA-01795 error.

Solutions for Dynamic and Large Value Lists

Flexing with Dynamic SQL

When value lists keep changing, dynamic SQL provides flexibility:

FOR i IN 1..10000 LOOP -- assume we have a large set
  IF MOD(i, 1000) = 1 THEN
    EXECUTE IMMEDIATE 'INSERT INTO temp_table VALUES(:value)' USING your_values(i);
  END IF;
END LOOP;


Temporary Tables for Large Lists

Temporary tables offer powerful solutions for larger datasets:

INSERT INTO temp_table (SELECT * FROM large_value_set WHERE conditions);
UPDATE your_table t SET t.column = (SELECT tmp.column FROM temp_table tmp WHERE t.id = tmp.id);
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Making bold moves with Architecture

Tap into the power of architecture-specific solutions. Platforms like Pythian house robust discussions on how table partitioning can supersede ORA-01795 errors.