如何使用 BigQuery SQL 查询从 Firestore 查询 noSQL 数据？

Question

I exported hierarchically structured data with Firebase hash-keys to BigQuery. However, since the data is not structured in tables, I don't know how to use SQL queries to get desired information. Is this possible in principle or do I need to convert / flatten the data into tables first? Google seems to advice visualizing data in Data Studio using BigQuery as source (not Firebase/Firestore directly). Yet, I cannot find any useful information / sample queries for this case. Thank you very much in advance.

Answer 1

I'm not familiar with the "hierarchically structured data with Firebase hash-keys", but the general guideline here to query such 'blob/text' data (from BigQuery perspective) is:

1. As you said, use separate pipeline to load / save the data into BQ table structure, or
2. Define a function to access your data. Since the function body could be JavaScript, you have the full flexibility to parse / read your text/blob data:

CREATE FUNCTION yourDataset.getValue(input STRING, key STRING)
RETURNS STRING
LANGUAGE js
AS """
// JavaScript code to read the data
""";