SELECT student_no,student_name,COUNT(course_no) AS course_num,SUM(score) AS total_score FROM student LEFT
2023-06-16 08:34
176
0
0
0
SELECT student_id, student_name FROM student
WHERE student_id NOT IN (SELECT student_id FROM course WHERE
2023-06-16 08:38
150
0
0
0
全连接指的是在两张或多张表中，返回所有符合两个表的记录，包括左表和右表的记录，即使右表或者左表某个字段没有匹配的记录。它与JOIN的区别在于：JOIN只返回两张表中存在匹配记录的结果，而FULL JOIN则返回所有
2023-06-17 09:37
147
0
0
0
语句用于从两个或多个表中返回所有匹配指定条件的记录。
LEFT JOIN 语法：
SELECT column_name(s)
FROM table1
LEFT JOIN table2
ON table1.colu
2023-06-20 09:32
161
0
0
0
：
SELECT student_id, name FROM Student WHERE student_id IN (SELECT student_id FROM Course WHERE teacher_nam
2023-06-20 09:32
205
0
0
0
SELECT stu_id,name FROM student
WHERE stu_id NOT IN
(SELECT stu_id FROM score
WHERE course IN
(SELECT cour
2023-06-20 09:32
165
0
0
0
SELECT stu_num, stu_name FROM student WHERE stu_num IN (SELECT stu_num FROM student WHERE stu_num != 01 IN
2023-06-20 09:33
173
0
0
0