从 csv 文件覆盖和 append 大查询表

Question

I have an existing bq table with date, stock id and stock price columns. Using bq load, I can either overwrite or append data from csv file. Using csv file,

1. want to overwrite rows in bq table if date and stock id already exist (updating price),
2. Else, want to append as new rows in bq table if if date and stock id does not exist in bq table

Answer 1

In that scenario you would want to to a two step process.

1. load the data to a staging table.
2. Issue a MERGE statement, and define the when matched and not matched criteria as you needed.

Documentation on the MERGE statement can be found here: https://cloud.google.com/bigquery/docs/reference/standard-sql/dml-syntax#merge_statement