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  3. Joining Data in SQL
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Checking multi-table joins

Have a look at the results for Albania from the previous query below. You can see that the 2015 fertility_rate has been paired with 2010 unemployment_rate, and vice versa.

name year fertility_rate unemployment_rate
Albania 2015 1.663 17.1
Albania 2010 1.663 14
Albania 2015 1.793 17.1
Albania 2010 1.793 14

Instead of four records, the query should return two: one for each year. The last join was performed on c.code = e.code, without also joining on year. Your task in this exercise is to fix your query by explicitly stating that both the country code and year should match!

Hướng dẫn

100 XP
  • Modify your query so that you are joining to economies on year as well as code.