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Data Integration (integrates additional data beyond what we have (join -…
Data Integration
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joins
inner join
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most often used, many databases are designed to not accept orders unless a customer account exists (referential integrity)
outer join (left outer, right outer, full outer)
left outer - similar to inner join, but also adds any other rows from the 1st table that doesn't have corresponding rows on the 2nd table
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right outer join - same result as an inner join but adds any other rows from the 2nd table that do not have corresponding rows on the 1st table
full outer join - same result as inner + left + right, any customer with or without orders is added to the resulting table
exercises
difference between inner join and left outer join is left outer includes rows from 1 column without corresponding values in another column.
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