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목록전체 글 (171)
조컴퓨터
1) MOD(id, 2) = 0 1-1) SELECT city FROM STATION WHERE MOD(id, 2) = 0; 1-1) 결과 2) 중복 체크 2-1) SELECT city FROM STATION WHERE MOD(id, 2) = 0 GROUP BY city; 2-1) 결과 SUCCESS!!
1) X = Y 1-1) SELECT X, Y FROM Functions WHERE X = Y GROUP BY X, Y 1-1) 결과 1-2) COUNT(*) SELECT X, Y, COUNT(*) FROM Functions WHERE X = Y GROUP BY X, Y HAVING COUNT(*) = 2 1-2) 결과 2) X1 = Y1 AND X2 = Y2 2-1) SELECT f1.X, f1.Y FROM Functions f1, Functions f2 WHERE f1.X = f2.Y AND f2.X = f1.Y AND f1.X < f1.Y -- f1.X f1.Y / 단, 이 경우에는 중첩되므로 f1.X < f1.Y 인 한 가지 경우만 사용 2-1) 결과 3) UNION 3-1) SELECT X, Y..
1) SELF JOIN 1-1) SELECT * FROM Weather w1, Weather w2 WHERE DATE_ADD(w1.recordDate, INTERVAL 1 DAY) = w2.recordDate AND w1.Temperature < w2.Temperature 1-1) 결과 {"headers": ["Id", "RecordDate", "Temperature", "Id", "RecordDate", "Temperature"], "values": [[1, "2015-01-01", 10, 2, "2015-01-02", 25], [3, "2015-01-03", 20, 4, "2015-01-04", 30]]} 2) w2.Id 2-1) SELECT w2.Id AS Id FROM Weather w1, Wea..
1) SELF JOIN 1-1) SELECT * FROM Employee e1, Employee e2 WHERE e1.Id = e2.ManagerId 1-1) 결과 {"headers": ["Id", "Name", "Salary", "ManagerId", "Id", "Name", "Salary", "ManagerId"], "values": [[3, "Sam", 60000, null, 1, "Joe", 70000, 3], [4, "Max", 90000, null, 2, "Henry", 80000, 4]]} 2) e1.Salary(매니저 급여) < e2.Salary(직원 급여) SELECT * FROM Employee e1, Employee e2 WHERE e1.Id = e2.ManagerId AND e1.S..
1) CASE WHEN 1-1) SELECT id , CASE WHEN month = "Jan" THEN revenue ELSE NULL END AS Jan_Revenue , CASE WHEN month = "Feb" THEN revenue ELSE NULL END AS Feb_Revenue , CASE WHEN month = "Mar" THEN revenue ELSE NULL END AS Mar_Revenue , CASE WHEN month = "Apr" THEN revenue ELSE NULL END AS Apr_Revenue , CASE WHEN month = "May" THEN revenue ELSE NULL END AS May_Revenue , CASE WHEN month = "Jun" THEN..
1) 정사각형 A=B AND B=C 1-1) SELECT CASE WHEN A=B AND B=C THEN 'Equilateral' ELSE '그외' END, A, B, C FROM TRIANGLES 2) 이등변 삼각형 2-1) SELECT CASE WHEN A=B AND B=C THEN 'Equilateral' WHEN A=B OR A=C OR B=C THEN 'Isosceles' ELSE '그외' END, A, B, C FROM TRIANGLES 2-2) SELECT CASE WHEN A=B AND B=C THEN 'Equilateral' WHEN A=B AND A+B>C OR A=C AND A+C>B OR B=C AND B+C>A THEN 'Isosceles' ELSE '그외' END, A, B, C..
1) salary * months = earnings 1-1) SELECT *, salary * months AS earnings FROM Employee 1-2) SELECT salary * months AS earnings FROM Employee GROUP BY earnings 1-3) SELECT salary * months AS earnings FROM Employee GROUP BY earnings ORDER BY earnings 1-4) SELECT salary * months AS earnings FROM Employee GROUP BY earnings ORDER BY earnings DESC 1-5) SELECT salary * months AS earnings FROM Employee ..