AWS Glue中使用Google BigQuery Connector的过程中，确实能够编写自定义查询。下面是一个基本的编写自定义查询的示例：

import com.amazonaws.services.glue.util.AWSGlueArgParser
import com.amazonaws.services.glue.DynamicFrame

import com.google.cloud.hadoop.io.bigquery.BigQueryConfiguration
import com.google.cloud.hadoop.io.bigquery.BigQueryStrings
import com.google.cloud.hadoop.io.bigquery.BigQueryUtils

import org.apache.hadoop.mapreduce.Job

import org.apache.spark.SparkContext
import org.apache.spark.sql.SparkSession
import org.apache.spark.sql.DataFrame
import org.apache.spark.sql.functions._

object CustomQuery {
  def main(sysArgs: Array[String]) {
  
    // Glue job-specific args.
    val glueArgs = Map("JOB_NAME" -> "custom-query")
    
    // Google BigQuery related args.
    val projectId = "my-big-query-project"
    val bucketName = "my-bucket"
    val datasetName = "my-dataset"
    val tableName = "my-table"
    val customQuery = "SELECT COUNT(*) FROM `my-dataset.my-table`"
  
    // Use AWSGlueArgParser to parse args.
    val args = AWSGlueArgParser.getResolvedOptions(sysArgs, Seq("JOB_NAME").toArray)
  
    // Set Spark context.
    val sparkContext = new SparkContext()
    val sparkSession = SparkSession
      .builder()
      .appName(args("JOB_NAME"))
      .getOrCreate()
  
    // Initialize the BigQuery Configuration.
    val bigQueryConf = BigQueryConfiguration.configureBigQueryOutput(projectId)
  
    // Set the Google Cloud storage bucket to export results to.
    bigQueryConf.set(BigQueryConfiguration.OUTPUT_FORMAT_OPTION, BigQueryStrings.CSV)
    bigQueryConf.set(BigQueryConfiguration.GCS_BUCKET_OPTION, s"gs://$bucketName")
  
    // Set up the Job, OutputFormat and Table to write to.
    val job = Job.getInstance(sparkContext.hadoopConfiguration)
    BigQueryConfiguration.configureBigQueryOutput(job, projectId, customQuery, datasetName, tableName)
  
    // Load DataFrame from customQuery.
    val df = sparkSession.read
      .format("