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2207/MySQL练习题/查询练习.md

@@ -274,7 +274,7 @@ FROM teachers t
 WHERE t.`name` LIKE '李%';
 
 #6.查询学过「张三」老师授课的同学的信息
-SELECT st.*
+SELECT DISTINCT st.*
 FROM students st, scores sc
 WHERE st.id = sc.student_id AND sc.course_id = (
 	SELECT c.id
@@ -293,10 +293,10 @@ HAVING COUNT(*) < 3;
 #8.查询至少有一门课与学号为" 01 "的同学所学相同的同学的信息
 SELECT st.*
 FROM students st, scores sc
-WHERE st.id = sc.student_id AND sc.course_id IN(
-	SELECT
-	FROM courses
-	WHERE student_id = '01'
+WHERE st.id = sc.student_id AND st.id <> '01' AND sc.course_id IN(
+	SELECT course_id
+	FROM scores s
+	WHERE s.student_id = '01'
 );
 
 #9.查询和" 01 "号的同学学习的课程完全相同的其他同学的信息