SQL练习题--某书第三章联结

20190422更新要注意6和7题后面举例说明了内联结外联结还有and和where的不同效果    #1. 为每个雇员行生成5个副本 SELECT E.empid,E.firstname,E.lastname,N.n FROM HR.Employees AS E CROSS JOIN dbo.Nums AS N WHERE N.n <=5 ORDER BY n,empid; #2.

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