Questions tagged [relational-algebra]

the study of relations (i.e., database tables) and relational operators (join, selection, projection, etc.) as a kind of algebraic structure.

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Use count() in relational algebra

Person(name, phone) Mike 456-789 Mike 123-456 John 230-785 $\dots \dots$ How to get those people who have more than one phone numbers with relational algebra? This sounds simple, but I am ...
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Expressing division in relational algebra in terms of other operations

So, I've been conferred upon the opinion that: Union, difference, cross product, selection, projection form the "complete set of relational operations". That is, any other relational operation ...