Type CASTs
In the video, you saw that type casts are a possible solution for data type issues. If you know that a certain column stores numbers as text, you can cast the column to a numeric form, i.e. to integer.
SELECT CAST(some_column AS integer)
FROM table;
Now, the some_column column is temporarily represented as integer instead of text, meaning that you can perform numeric calculations on the column.
Deze oefening maakt deel uit van de cursus
Introduction to Relational Databases in SQL
Oefeninstructies
- Execute the given sample code.
- As it doesn't work, add an
integertype cast at the right place and execute it again.
Praktische interactieve oefening
Probeer deze oefening eens door deze voorbeeldcode in te vullen.
-- Calculate the net amount as amount + fee
SELECT transaction_date, amount + fee AS net_amount
FROM transactions;