SQL

Various manipulation with SQL query, such as:

  • ISO calendar: When we create yearly, monthly or weekly report, we are sometimes beset by problem about calendar. Like the last day of year 2018 (2018-12-31) is regarded as one day of 2018 or 2019 ? Or the last day of year 2018 is considered as one day of 2018’s last week or 2019’s first week? It’s a question about ISO calendar, and the answer depends on what we want. In my blog, I talked about how to handle ISO calendar with Teradata Database SQL.
  • Data processing: we can take advantage of SQL query to improve pandas dataframe processing performance.