Data Querying

Verification Requirement

All queries MUST be executed with bq and verified before inclusion. Never include unverified queries or fabricated data.

Query Process

1. Dry run: Validate syntax and check cost

   bq query --project_id=<PROJECT_ID> --use_legacy_sql=false --dry_run "SELECT ..."
   

   Cost: ~$5/TB. <1GB is light, 2GB+ needs optimization.

2. Execute: Run and confirm results

   bq query --project_id=<PROJECT_ID> --use_legacy_sql=false --format=csv "SELECT ..."
   

3. Learn: Study existing queries in project docs for patterns.

Query Design

• Specify exact date ranges
• Filter partitioned tables by partition key
• Avoid correlated subqueries (use JOINs/CTEs)
• Filter early with CTEs before joining large tables

Documentation

1. Execute exact query with bq
2. Copy real output only
3. State time period and what query measures