31. 以下哪項不是有效的SQL指令?
(A)SELECT * FROM Lawyers WHERE firmName LIKE '% and %';
(B)SELECT COUNT(*) FROM Firms WHERE employees < 100;
(C)SELECT firmLoc, COUNT(*) FROM Firms WHERE employees < 100;
(D)SELECT firmLoc, COUNT(*) FROM Firms WHERE employees < 100 GROUP BY firmLoc;
詳解 (共 2 筆)
未解鎖
從以下兩條說明,可以知道,如果selec...
未解鎖
COUNT(*) 要搭 GROUP B...