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Exercise

Joining tables

Tables in relational databases usually have key columns of unique record identifiers. This lets us build pipelines that combine tables using SQL's JOIN operation, instead of having to combine data after importing it.

The records in hpd311calls often concern issues, like leaks or heating problems, that are exacerbated by weather conditions. In this exercise, you'll join weather data to call records along their common date columns to get everything in one dataframe. You can assume these columns have the same data type.

pandas is loaded as pd, and the database engine, engine, has been created.

Note: The SQL checker is picky about join table order -- it expects specific tables on the left and the right.

Instructions

100 XP
  • Complete the query to join weather to hpd311calls by their date and created_date columns, respectively.
  • Query the database and assign the resulting dataframe to calls_with_weather.
  • Print the first few rows of calls_with_weather to confirm all columns were joined.