使用BigQuery Python客户端库中提供的google.cloud.bigquery.helpers.compare_query_results函数比较两个查询结果。该函数返回True或False，表示两个结果是否相等。示例代码如下所示：

from google.cloud import bigquery

client = bigquery.Client()

query1 = "SELECT COUNT(*) FROM mydataset.mytable WHERE age > 20;"
query2 = "SELECT COUNT(*) FROM mydataset.mytable WHERE age > 30;"

job_config = bigquery.QueryJobConfig()

# Start Query 1
query_job1 = client.query(query1, job_config=job_config)
result1 = query_job1.result()

# Start Query 2
query_job2 = client.query(query2, job_config=job_config)
result2 = query_job2.result()

# Compare results
equal = bigquery.helpers.compare_query_results(result1, result2)

if equal:
    print("Query results are equal.")
else:
    print("Query results are not equal.")

该代码示例执行了两个查询并比较了它们的结果是否相等。如果结果相等，则输出'Query results are equal.”，否则输出'Query results are not equal.”。注意：上述示例代码仅用于演示目的。在实际应用中，请根据自己的需求进行适当修改。