| 7. 1. 2. Three different types of joins: |
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Inner joins - Return a row only when the columns in the join contain values that satisfy the join condition. |
This means that if a row has a null value in one of the columns in the join condition, that row isn't returned. |
Outer joins - Can return a row even when one of the columns in the join condition contains a null value. |
Self joins - Return rows joined on the same table. |