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2207/MySQL数据库操作综合练习题答案.md

@@ -578,5 +578,50 @@ INSERT INTO travel (tid, time, position, money, aid, count) VALUES
 (1, '5天', '八达岭', 3000, 101, 10),
 (2, '7天', '水长城', 5000, 101, 14),
 (3, '8天', '水长城', 6000, 102, 11);
+
+#4
+SELECT a.*
+FROM travel t, agency a
+WHERE t.aid =a.id
+GROUP BY a.id
+HAVING COUNT(*) = (
+	SELECT COUNT(*)
+	FROM travel t, agency a
+	WHERE t.aid =a.id
+	GROUP BY a.id
+	ORDER BY COUNT(*) DESC
+	LIMIT 1
+);
+
+#5
+SELECT t.*
+FROM travel t
+WHERE t.count = (
+	SELECT t.count
+	FROM travel t
+	ORDER BY t.count DESC
+	LIMIT 1
+);
+
+#6
+SELECT *
+FROM travel t
+WHERE t.money < 5000;
+
+#7
+SELECT a.`name`
+FROM travel t, agency a
+WHERE t.aid =a.id AND t.money = (
+	SELECT t.money
+	FROM travel t, agency a
+	WHERE t.aid =a.id
+	ORDER BY t.money DESC
+	LIMIT 1
+);
+
+#8
+SELECT SUM(t.time)
+FROM travel t, agency a
+WHERE t.aid =a.id AND a.`name` = '青年旅行社';
 ```