Instruction MCP Server

# Debugging Data Issues ## Common Issues ### Missing Data - Check for NULL values vs empty strings - Verify JOIN conditions aren't dropping rows - Look for implicit filters in WHERE clauses ### Unexpected Results - Verify date ranges are inclusive/exclusive as expected - Check for duplicate rows affecting aggregations - Confirm timezone handling is consistent ### Performance Issues - Check query execution plan - Look for missing indexes on JOIN/WHERE columns - Consider partitioning for large datasets ## Debugging Checklist 1. [ ] Run query on smaller dataset first 2. [ ] Check row counts at each step 3. [ ] Validate sample rows manually 4. [ ] Compare against known good baseline 5. [ ] Test edge cases (nulls, zeros, boundaries)