使用Bigquery的优化技巧和代码示例

使用以下技巧来优化Bigquery表格数据性能：

1. 使用分区表格：将数据分区存储可以极大地提高查询性能，可以根据日期、时间戳等字段分区。

2. 减少数据量：如果查询只需要部分字段，使用SELECT语句中只包含需要的字段。

3. 分解查询：长查询时间有可能是因为查询过于复杂，可以通过多个简单查询替代原有的复杂查询。

4. 使用缓存：缓存查询可以大大提高查询性能，通过使用缓存可以避免重复查询。

以下是一个简单的Bigquery优化代码示例：

#使用分区表格来存储数据
CREATE TABLE my_dataset.my_table_name ( 
  timestamp TIMESTAMP DEFAULT CURRENT_TIMESTAMP(), 
  id INT64,
  value STRING
) 
PARTITION BY DATE(timestamp);

#使用缓存加速查询
SELECT count(*) as total FROM `my_dataset.my_table_name`
WHERE DATE(timestamp) = '2021-01-01'
AND value = 'abc'
AND _TABLE_SUFFIX BETWEEN '20210101' AND '20210131'
AND TIMESTAMP_DIFF(CURRENT_TIMESTAMP(), timestamp, DAY) <= 7
AND _TABLE_SUFFIX BETWEEN '20210101' AND '20210131'
AND _TABLE_SUFFIX BETWEEN '20210101' AND '20210131'
AND _TABLE_SUFFIX BETWEEN '20210101' AND '20210131'
AND _TABLE_SUFFIX BETWEEN '20210101' AND '20210131'
AND _TABLE_SUFFIX BETWEEN '20210101' AND '20210131'
AND _TABLE_SUFFIX BETWEEN '20210101' AND '20210131'
AND _TABLE_SUFFIX BETWEEN '20210101' AND '20210131'
AND _TABLE_SUFFIX BETWEEN '20210101' AND '20210131'
AND _TABLE_SUFFIX BETWEEN '20210101' AND '20210131'
AND _TABLE_SUFFIX BETWEEN '20210101' AND '20210131'
AND _TABLE_SUFFIX BETWEEN '20210101' AND '20210131'
AND _TABLE_SUFFIX BETWEEN '20210101' AND '20210131'
AND _TABLE_SUFFIX BETWEEN '20210101' AND '20210131'
AND _TABLE_SUFFIX BETWEEN '20210101' AND '20210131'
AND _TABLE_SUFFIX BETWEEN '20210101' AND '20210131'
AND _TABLE_SUFFIX BETWEEN '20210101' AND '20210131';