R2 SQL Gotchas

Limitations, troubleshooting, and common pitfalls for R2 SQL.

Critical Limitations

No Workers Binding

Cannot call R2 SQL from Workers/Pages code - no binding exists.

// ❌ This doesn't exist
export default {
  async fetch(request, env) {
    const result = await env.R2_SQL.query("SELECT * FROM table");  // Not possible
    return Response.json(result);
  }
};

Solutions:

• HTTP API from external systems (not Workers)
• PyIceberg/Spark via r2-data-catalog REST API
• For Workers, use D1 or external databases

ORDER BY Limitations

Can only order by:

1. Partition key columns - Always supported
2. Aggregation functions - Supported via shuffle strategy

Cannot order by regular non-partition columns.

-- ✅ Valid: ORDER BY partition key
SELECT * FROM logs.requests ORDER BY timestamp DESC LIMIT 100;

-- ✅ Valid: ORDER BY aggregation
SELECT region, SUM(amount) FROM sales.transactions
GROUP BY region ORDER BY SUM(amount) DESC;

-- ❌ Invalid: ORDER BY non-partition column
SELECT * FROM logs.requests ORDER BY user_id;

-- ❌ Invalid: ORDER BY alias (must repeat function)
SELECT region, SUM(amount) as total FROM sales.transactions
GROUP BY region ORDER BY total;  -- Use ORDER BY SUM(amount)

Check partition spec: DESCRIBE namespace.table_name

SQL Feature Limitations

Feature	Supported	Notes
SELECT, WHERE, GROUP BY, HAVING	✅	Standard support
COUNT, SUM, AVG, MIN, MAX	✅	Standard aggregations
ORDER BY partition/aggregation	✅	See above
LIMIT	✅	Max 10,000
Column aliases	❌	No AS alias
Expressions in SELECT	❌	No col1 + col2
ORDER BY non-partition	❌	Fails at runtime
JOINs, subqueries, CTEs	❌	Denormalize at write time
Window functions, UNION	❌	Use external engines
INSERT/UPDATE/DELETE	❌	Use PyIceberg/Pipelines
Nested columns, arrays, JSON	❌	Flatten at write time

Workarounds:

• No JOINs: Denormalize data or use Spark/PyIceberg
• No subqueries: Split into multiple queries
• No aliases: Accept generated names, transform in app

Common Errors

"Column not found"

Cause: Typo, column doesn't exist, or case mismatch
Solution: DESCRIBE namespace.table_name to check schema

"Type mismatch"

-- ❌ Wrong types
WHERE status = '200'              -- string instead of integer
WHERE timestamp > '2025-01-01'    -- missing time/timezone

-- ✅ Correct types
WHERE status = 200
WHERE timestamp > '2025-01-01T00:00:00Z'

"ORDER BY column not in partition key"

Cause: Ordering by non-partition column
Solution: Use partition key, aggregation, or remove ORDER BY. Check: DESCRIBE table

"Token authentication failed"

# Check/set token
echo $WRANGLER_R2_SQL_AUTH_TOKEN