![]() Query 13: Make a list of all project numbers for projects that involve an employee whose last name is 'Smith' as a worker or as a manager of the department that controls the project. ![]() The set operations apply only to union compatible relations the two relations must have the same attributes and the attributes must appear in the same order.The resulting relations of these set operations are sets of tuples duplicate tuples are eliminated from the result.There is a union operation (UNION), and in some versions of SQL there are set difference (MINUS) and intersection (INTERSECT) operations.SQL has directly incorporated some set operations.Q12A: SELECT DISTINCT SALARY FROMIJMPLOYEE.For example, the result of Q12 may have duplicate SALARY values whereas Q12A does not have any duplicate values.To eliminate duplicate tuples in a query result, the keyword DISTINCT is used.University Of Palestine Fundamentals ofDatabase SystemsFourth EditionEl Masri & Navathe Chapter 8 (Cont.) SQL-99: Schema Definition, Basic Constraints, and QueriesÄatabase Management CH 8 University Of Palestine
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