1 SELECT T1.C#, 2 3 ROUND(T1.AVG_SCORE, 2) AVG_SCORE, 4 5 ROUND(T2.PASS_COUNT / T1.ALL_COUNT, 2) PASS_POINT 6 7 FROM (SELECT DISTINCT C#, 8 9 COUNT(1) OVER(PARTITION BY C# ORDER BY C#) ALL_COUNT, 10 11 AVG(SCORE) OVER(PARTITION BY C# ORDER BY C#) AVG_SCORE 12 13 FROM SC) T1, 14 15 (SELECT DISTINCT C#, 16 17 COUNT(1) OVER(PARTITION BY C# ORDER BY C#) PASS_COUNT 18 19 FROM SC 20 21 WHERE SCORE >= 60) T2 22 23 WHERE T1.C# = T2.C# 24 25 ORDER BY AVG_SCORE, PASS_POINT DESC
Union，对两个结果集进行并集操作，不包括重复行，同时进行默认规则的排序； Union All，对两个结果集进行并集操作，包括重复行，不进行排序； Intersect，对两个结果集进行交集操作，不包括重复行，同时进行默认规则的排序； Minus，对两个结果集进行差操作，不包括重复行，同时进行默认规则的排序。
SQL查询强化训练
摘自 http://blog.163.com/ky_199/blog/static/143176020125711452318/
http://yabar.iteye.com/blog/583203 更全
http://www.iteye.com/wiki/blog/1143788更多练习的sql
SQL查询强化训练
以下案例用到以下表
Student(S#,Sname,Sage,Ssex) 学生表
S#：学生编号，字符串型
Sname： 学生姓名，字符串型
Sage：年龄 ，数值型
Ssex：性别，字符串型
Course(C#,Cname,T#) 课程表
C#：课程编号 ，字符串型 （企业管理001，马列002，UML 003，数据库004，英语006）
Cname：课程名称 ，字符串型
T#：教师编号，字符串型
SC(S#,C#,score) 成绩表
S#：学生编号 ，字符串型
C#：课程编号 ，字符串型
score：成绩，数值型
Teacher(T#,Tname) 教师表
T#：教师编号 ，字符串型
Tname：教师姓名，字符串型
注：合格的标准为课程的成绩大于等于60分，带#号的字段表示主键或有外键关联
**********************************************************************************************************
View Code
1 SQL脚本预准备如下：
2
3 create table COURSE
4
5 (
6
7 C# VARCHAR2(20),
8
9 CNAME VARCHAR2(20),
10
11 T# VARCHAR2(20)
12
13 )
14
15 create table SC
16
17 (
18
19 S# VARCHAR2(20),
20
21 C# VARCHAR2(20),
22
23 SCORE NUMBER(5,2)
24
25 )
26
27 create table STUDENT
28
29 (
30
31 S# VARCHAR2(20),
32
33 SNAME VARCHAR2(20),
34
35 SAGE NUMBER,
36
37 SSEX VARCHAR2(20)
38
39 )
40
41 create table TEACHER
42
43 (
44
45 T# VARCHAR2(20),
46
47 TNAME VARCHAR2(20)
48
49 )
50
51 insert into course (C#, CNAME, T#)
52
53 values ('001', '企业管理', '9001');
54
55
56
57 insert into course (C#, CNAME, T#)
58
59 values ('002', '马列', '9002');
60
61
62
63 insert into course (C#, CNAME, T#)
64
65 values ('003', 'UML', '9006');
66
67
68
69 insert into course (C#, CNAME, T#)
70
71 values ('004', '数据库', '9004');
72
73
74
75 insert into course (C#, CNAME, T#)
76
77 values ('006', '英语', '9006');
78
79
80
81 insert into sc (S#, C#, SCORE)
82
83 values ('1008', '003', 85.00);
84
85
86
87 insert into sc (S#, C#, SCORE)
88
89 values ('1008', '004', 21.00);
90
91
92
93 insert into sc (S#, C#, SCORE)
94
95 values ('1008', '001', 47.00);
96
97
98
99 insert into sc (S#, C#, SCORE)
100
101 values ('1005', '006', 99.00);
102
103
104
105 insert into sc (S#, C#, SCORE)
106
107 values ('1012', '002', 22.00);
108
109
110
111 insert into sc (S#, C#, SCORE)
112
113 values ('1001', '001', 60.00);
114
115
116
117 insert into sc (S#, C#, SCORE)
118
119 values ('1001', '002', 88.00);
120
121
122
123 insert into sc (S#, C#, SCORE)
124
125 values ('1001', '004', 20.00);
126
127
128
129 insert into sc (S#, C#, SCORE)
130
131 values ('1002', '006', 20.00);
132
133
134
135 insert into sc (S#, C#, SCORE)
136
137 values ('1003', '002', 78.00);
138
139
140
141 insert into sc (S#, C#, SCORE)
142
143 values ('1003', '006', 90.00);
144
145
146
147 insert into sc (S#, C#, SCORE)
148
149 values ('1003', '001', 97.00);
150
151
152
153 insert into sc (S#, C#, SCORE)
154
155 values ('1003', '003', 72.00);
156
157
158
159 insert into sc (S#, C#, SCORE)
160
161 values ('1004', '002', 88.00);
162
163
164
165 insert into sc (S#, C#, SCORE)
166
167 values ('1004', '006', 62.00);
168
169
170
171 insert into sc (S#, C#, SCORE)
172
173 values ('1006', '001', 32.00);
174
175
176
177 insert into sc (S#, C#, SCORE)
178
179 values ('1006', '003', 99.00);
180
181
182
183 insert into sc (S#, C#, SCORE)
184
185 values ('1006', '004', 69.00);
186
187
188
189 insert into sc (S#, C#, SCORE)
190
191 values ('1006', '006', 73.00);
192
193
194
195 insert into sc (S#, C#, SCORE)
196
197 values ('1007', '001', 77.00);
198
199
200
201 insert into sc (S#, C#, SCORE)
202
203 values ('1007', '002', 54.00);
204
205
206
207 insert into sc (S#, C#, SCORE)
208
209 values ('1007', '003', 83.00);
210
211
212
213 insert into sc (S#, C#, SCORE)
214
215 values ('1008', '006', 12.00);
216
217
218
219 insert into sc (S#, C#, SCORE)
220
221 values ('1008', '002', 55.00);
222
223
224
225 insert into sc (S#, C#, SCORE)
226
227 values ('1009', '002', 34.00);
228
229
230
231 insert into sc (S#, C#, SCORE)
232
233 values ('1010', '002', 84.00);
234
235
236
237 insert into sc (S#, C#, SCORE)
238
239 values ('1010', '006', 87.00);
240
241
242
243 insert into sc (S#, C#, SCORE)
244
245 values ('1011', '006', 99.00);
246
247
248
249 insert into sc (S#, C#, SCORE)
250
251 values ('1012', '004', 87.00);
252
253
254
255 insert into sc (S#, C#, SCORE)
256
257 values ('1002', '002', 75.00);
258
259
260
261 insert into sc (S#, C#, SCORE)
262
263 values ('1011', '001', 12.00);
264
265
266
267 insert into sc (S#, C#, SCORE)
268
269 values ('1011', '002', 76.00);
270
271
272
273 insert into sc (S#, C#, SCORE)
274
275 values ('1011', '004', 44.00);
276
277
278
279 insert into sc (S#, C#, SCORE)
280
281 values ('1012', '001', 89.00);
282
283
284
285 insert into student (S#, SNAME, SAGE, SSEX)
286
287 values ('1001', 'kangyue', 29, 'male');
288
289
290
291 insert into student (S#, SNAME, SAGE, SSEX)
292
293 values ('1002', 'wangyu', 29, 'male');
294
295
296
297 insert into student (S#, SNAME, SAGE, SSEX)
298
299 values ('1003', '王新刚', 30, '');
300
301
302
303 insert into student (S#, SNAME, SAGE, SSEX)
304
305 values ('1004', '鲁豫', 27, 'famale');
306
307
308
309 insert into student (S#, SNAME, SAGE, SSEX)
310
311 values ('1005', 'sanhui', 29, 'male');
312
313
314
315 insert into student (S#, SNAME, SAGE, SSEX)
316
317 values ('1006', '梦涵', 28, 'famale');
318
319
320
321 insert into student (S#, SNAME, SAGE, SSEX)
322
323 values ('1007', 'yangdayong', 30, 'male');
324
325
326
327 insert into student (S#, SNAME, SAGE, SSEX)
328
329 values ('1008', 'sunguoqiang', 30, 'male');
330
331
332
333 insert into student (S#, SNAME, SAGE, SSEX)
334
335 values ('1009', '李宏利', 49, 'male');
336
337
338
339 insert into student (S#, SNAME, SAGE, SSEX)
340
341 values ('1010', '小心', 20, 'famale');
342
343
344
345 insert into student (S#, SNAME, SAGE, SSEX)
346
347 values ('1011', '小泉', 99, 'male');
348
349
350
351 insert into student (S#, SNAME, SAGE, SSEX)
352
353 values ('1012', '特里', 39, 'male');
354
355
356
357 insert into teacher (T#, TNAME)
358
359 values ('9001', '崔老师');
360
361
362
363 insert into teacher (T#, TNAME)
364
365 values ('9002', '颜老师');
366
367
368
369 insert into teacher (T#, TNAME)
370
371 values ('9003', '岳老师');
372
373
374
375 insert into teacher (T#, TNAME)
376
377 values ('9004', '夏老师');
378
379
380
381 insert into teacher (T#, TNAME)
382
383 values ('9005', '杨老师');
384
385
386
387 insert into teacher (T#, TNAME)
388
389 values ('9006', '叶平');
390
391
392
393 insert into teacher (T#, TNAME)
394
395 values ('9007', '梦老师');
*************************************************************************************************************************
完成以下语句：
1、查询001课程比002课程成绩高的所有学生的学号；
View Code
1 SELECT T2.S#--, T2.COURSE_001, T2.COURSE_002 2 3 FROM 4 5 ( 6 7 SELECT T1.S#, SUM(T1.COURSE_001) COURSE_001, SUM(T1.COURSE_002) COURSE_002 8 9 FROM 10 11 ( 12 13 SELECT S#, 14 15 CASE WHEN C# = '001'THEN SCORE 16 17 ELSE 0 18 19 END COURSE_001, 20 21 CASE WHEN C# = '002'THEN SCORE 22 23 ELSE 0 24 25 END COURSE_002 26 27 FROM SC 28 29 ) T1 30 31 GROUP BY S# 32 33 ) T2 34 35 WHERE T2.COURSE_001 > T2.COURSE_002
2、查询平均成绩大于60分的同学的学号和平均成绩；
View Code
1 SELECT S#, AVG(SCORE) SCORE 2 3 FROM SC 4 5 GROUP BY S# 6 7 HAVING AVG(SCORE) >60
3、查询所有同学的学号、姓名、选课数、总成绩；
View Code
1 SELECT T1.S#, T1.SNAME, T2.CNT, T2.TOTAL_SCORE 2 3 FROM STUDENT T1, 4 5 ( 6 7 SELECT S#, COUNT(1) CNT, SUM(SCORE) TOTAL_SCORE 8 9 FROM SC 10 11 GROUP BY S# 12 13 ) T2 14 15 WHERE T1.S# = T2.S#
4、查询姓“李”的老师的个数；
View Code
1 SELECT COUNT(1) FROM TEACHER WHERE TNAME LIKE '李%';
5、查询没学过“叶平”老师课的同学的学号、姓名；
View Code
1 SELECT T.S#, T.SNAME 2 3 FROM STUDENT T 4 5 WHERE T.S# NOT IN (SELECT S# 6 7 FROM SC 8 9 WHERE C# IN (SELECT C# 10 11 FROM TEACHER T1, COURSE T2 12 13 WHERE T1.T# = T2.T# 14 15 AND TNAME = '叶平'));
6、查询学过“001并且也学过编号002”课程的同学的学号、姓名；
View Code
1 SELECT T1.S#, T1.SNAME
2
3 FROM STUDENT T1
4
5 WHERE EXISTS (SELECT T2.S#
6
7 FROM SC T2
8
9 WHERE T2.C# IN ('001', '002')
10
11 AND T2.S# = T1.S#
12
13 GROUP BY T2.S#
14
15 HAVING COUNT(1) > 1);
32.--法一： 33. 34.SELECT c.s#,c.sname FROM t_wolf_student c WHERE c.s# IN( 35. 36.SELECT a.s# FROM t_wolf_sc a WHERE a.c#='001' 37. 38.INTERSECT 39. 40.SELECT b.s# FROM t_wolf_sc b WHERE b.c#='002'); 41. 42.--法二： 43. 44.SELECT a.s#,a.sname FROM t_wolf_student a,t_wolf_sc b WHERE a.s#=b.s# AND b.c#='001' AND EXISTS 45. 46.(SELECT * FROM t_wolf_sc c WHERE c.c#='002' AND c.s#=b.s#); 47.
7、查询学过“叶平”老师所教的所有课的同学的学号、姓名；
View Code
1 SELECT T.S#, T.SNAME 2 3 FROM STUDENT T 4 5 WHERE T.S# IN (SELECT S# 6 7 FROM SC 8 9 WHERE C# IN (SELECT C# 10 11 FROM TEACHER T1, COURSE T2 12 13 WHERE T1.T# = T2.T# 14 15 AND TNAME = '叶平'));
8、查询课程编号001的成绩比课程编号002课程低的所有同学的学号、姓名；
View Code
1 SELECT T3.S#, T3.SNAME--, T2.COURSE_001, T2.COURSE_002 2 3 FROM 4 5 ( 6 7 SELECT T1.S#, SUM(T1.COURSE_001) COURSE_001, SUM(T1.COURSE_002) COURSE_002 8 9 FROM 10 11 ( 12 13 SELECT S#, 14 15 CASE WHEN C# = '001'THEN SCORE 16 17 ELSE 0 18 19 END COURSE_001, 20 21 CASE WHEN C# = '002'THEN SCORE 22 23 ELSE 0 24 25 END COURSE_002 26 27 FROM SC 28 29 ) T1 30 31 GROUP BY S# 32 33 ) T2, 34 35 STUDENT T3 36 37 WHERE T2.S# = T3.S# 38 39 AND T2.COURSE_001 < T2.COURSE_002
9、查询所有课程成绩小于60分的同学的学号、姓名；
View Code
1 SELECT T.S#, T.SNAME FROM STUDENT T 2 3 WHERE EXISTS (SELECT DISTINCT T1.S# 4 5 FROM SC T1 6 7 WHERE NOT EXISTS (SELECT 1 8 9 FROM SC T2 10 11 WHERE T2.SCORE > 60 12 13 AND T2.S# = T1.S#) 14 15 AND T1.S# = T.S#)
这里需要注意的：
View Code
1 有两个简单例子，以说明 “exists”和“in”的效率问题 2 3 1) select * from T1 where exists(select 1 from T2 where T1.a=T2.a) ; 4 5 T1数据量小而T2数据量非常大时，T1<<T2 时，1) 的查询效率高。 6 7 2) select * from T1 where T1.a in (select T2.a from T2) ; 8 9 T1数据量非常大而T2数据量小时，T1>>T2 时，2) 的查询效率高。 10 11 exists 用法： 12 13 请注意 1）句中的有颜色字体的部分 ，理解其含义； 14 15 其中 “select 1 from T2 where T1.a=T2.a” 相当于一个关联表查询，相当于 16 17 “select 1 from T1,T2 where T1.a=T2.a” 18 19 但是，如果你当当执行 1） 句括号里的语句，是会报语法错误的，这也是使用exists需要注意的地方。 20 21 “exists（xxx）”就表示括号里的语句能不能查出记录，它要查的记录是否存在。 22 23 因此“select 1”这里的 “1”其实是无关紧要的，换成“*”也没问题，它只在乎括号里的数据能不能查找出来，是否存在这样的记录，如果存在，这 1） 句的where 条件成立。 24 25 26 27 in 的用法： 28 29 继续引用上面的例子 30 31 “2) select * from T1 where T1.a in (select T2.a from T2) ” 32 33 这里的“in”后面括号里的语句搜索出来的字段的内容一定要相对应，一般来说，T1和T2这两个表的a字段表达的意义应该是一样的，否则这样查没什么意义。 34 35 打个比方：T1，T2表都有一个字段，表示工单号，但是T1表示工单号的字段名叫“ticketid”，T2则为“id”，但是其表达的意义是一样的，而且数据格式也是一样的。这时，用 2）的写法就可以这样： 36 37 “select * from T1 where T1.ticketid in (select T2.id from T2) ” 38 39 Select name from employee where name not in (select name from student); 40 41 Select name from employee where not exists (select name from student); 42 43 第一句SQL语句的执行效率不如第二句。 44 45 通过使用EXISTS，Oracle会首先检查主查询，然后运行子查询直到它找到第一个匹配项，这就节省了时间。Oracle在执行IN子查询时，首先执行子查询，并将获得的结果列表存放在一个加了索引的临时表中。在执行子查询之前，系统先将主查询挂起，待子查询执行完毕，存放在临时表中以后再执行主查询。这也就是使用EXISTS比使用IN通常查询速度快的原因
10、 查询没有学全所有课的同学的学号、姓名；
View Code
1 SELECT T1.S#, T1.SNAME FROM STUDENT T1 2 3 WHERE NOT EXISTS (SELECT S# 4 5 FROM (SELECT S#, COUNT(1) CNT FROM SC GROUP BY S#) T 6 7 WHERE CNT = (SELECT COUNT(1) FROM COURSE) 8 9 AND T.S# = T1.S#) 10 11 ORDER BY T1.S#
11、 查询至少有一门课与学号为1001的同学所学相同的同学的学号和姓名;
View Code
1 SELECT T1.S#, T1.SNAME 2 3 FROM STUDENT T1, 4 5 (SELECT DISTINCT S# 6 7 FROM SC 8 9 WHERE C# IN (SELECT C# FROM SC WHERE S# = 1001) 10 11 AND S# != 1001) T2 12 13 WHERE T1.S# = T2.S#
12、 查询至少学过学号为1001同学所有课的其他同学学号和姓名;
View Code
1 SELECT DISTINCT T4.S#, T4.SNAME 2 3 FROM (SELECT T1.S#, T1.CNT1, T2.CNT2, COUNT(1) OVER(PARTITION BY S#) CNT 4 5 FROM (SELECT S#, C#, COUNT(1) OVER(PARTITION BY S#) CNT1 6 7 FROM SC 8 9 WHERE S# != '1001' 10 11 GROUP BY S#, C#) T1, 12 13 (SELECT C#, COUNT(1) OVER(PARTITION BY S#) CNT2 14 15 FROM SC 16 17 WHERE S# = '1001') T2 18 19 WHERE T1.C# = T2.C# 20 21 AND T1.CNT1 >= T2.CNT2) T3, 22 23 STUDENT T4 24 25 WHERE T4.S# = T3.S# 26 27 AND T3.CNT >= T3.CNT2
13、 把SC表中叶平老师教的课的成绩都更改为此课程的平均成绩;（暂时未发现其他好办法）
View Code
1 UPDATE SC SET SC.SCORE=( 2 3 WITH TT AS( 4 5 SELECT T.C#, AVG(T.SCORE) SCO 6 7 FROM SC T 8 9 WHERE T.C# IN (SELECT T1.C# 10 11 FROM COURSE T1, TEACHER T2 12 13 WHERE T1.T# = T2.T# 14 15 AND T2.TNAME = '叶平') 16 17 GROUP BY T.C# 18 19 ) 20 21 SELECT SCO FROM TT WHERE TT.C# = SC.C# 22 23 ) 24 25 WHERE EXISTS 26 27 (SELECT T1.C# 28 29 FROM COURSE T1, TEACHER T2 30 31 WHERE T1.T# = T2.T# 32 33 AND T2.TNAME = '叶平' 34 35 AND T1.C# = SC.C# 36 37 )
14、 查询和1002号的同学学习的课程完全相同的其他同学学号和姓名;
View Code
1 SELECT DISTINCT T4.S#, T4.SNAME 2 3 FROM (SELECT T1.S#, T2.CNT2, COUNT(1) OVER(PARTITION BY S#) CNT 4 5 FROM (SELECT S#, C#, COUNT(1) OVER(PARTITION BY S#) CNT1 6 7 FROM SC 8 9 WHERE S# != '1002' 10 11 GROUP BY S#, C#) T1, 12 13 (SELECT C#, COUNT(1) OVER(PARTITION BY S#) CNT2 14 15 FROM SC 16 17 WHERE S# = '1002') T2 18 19 WHERE T1.C# = T2.C# 20 21 AND T1.CNT1 = T2.CNT2) T3, 22 23 STUDENT T4 24 25 WHERE T4.S# = T3.S# 26 27 AND T3.CNT = T3.CNT2
15、 删除学习“叶平”老师课的SC表记录;
View Code
1 DELETE FROM SC T1 2 3 WHERE EXISTS (SELECT 1 4 5 FROM COURSE T2 6 7 WHERE T2.T# IN (SELECT T# FROM TEACHER WHERE TNAME = '叶平') 8 9 AND T2.C# = T1.C#)
16、 向SC表中插入一些记录，这些记录要求符合以下条件：没有上过编号002课程的同学学号、002、002号课的平均成绩
View Code
1 INSERT INTO SC WITH TT AS 2 3 (SELECT ROUND(AVG(SCORE), 2) AVG_SCORE FROM SC WHERE C# = '002') 4 5 SELECT DISTINCT T1.S#, '002', TT.AVG_SCORE 6 7 FROM SC T1, TT 8 9 WHERE NOT EXISTS (SELECT T2.S# 10 11 FROM SC T2 12 13 WHERE T2.C# = '002' 14 15 AND T2.S# = T1.S#)
17、 按平均成绩从高到低显示所有学生的“数据库”、“企业管理”、“英语”三门的课程成绩，按如下形式显示：学生ID,,数据库,企业管理,英语,有效课程数,有效平均分；
View Code
1 SELECT S#, ENTERPRISE_, DATABASE_, ENGLISH_, SCORE_CNT,
2
3 TRUNC((NVL(ENTERPRISE_, 0) + NVL(DATABASE_, 0) + NVL(ENGLISH_, 0))/SCORE_CNT, 2) AVG_SCORE
4
5 FROM
6
7 (
8
9 SELECT S#, ENTERPRISE_, DATABASE_, ENGLISH_,
10
11 DECODE(ENTERPRISE_, '', DECODE(DATABASE_, '', DECODE(ENGLISH_, '', 0, 1), DECODE(ENGLISH_, '', 1, 2)), DECODE(DATABASE_, '',DECODE(ENGLISH_, '', 1, 2), DECODE(ENGLISH_,'',2, 3))) SCORE_CNT
12
13 FROM(
14
15 SELECT S#, SUM(ENTERPRISE_) ENTERPRISE_, SUM(DATABASE_) DATABASE_, SUM(ENGLISH_) ENGLISH_
16
17 FROM
18
19 (
20
21 SELECT S#,
22
23 CASE WHEN C# = '001' THEN SCORE
24
25 ELSE NULL
26
27 END ENTERPRISE_,
28
29 CASE WHEN C# = '004' THEN SCORE
30
31 ELSE NULL
32
33 END DATABASE_,
34
35 CASE WHEN C# = '006' THEN SCORE
36
37 ELSE NULL
38
39 END ENGLISH_
40
41 FROM SC
42
43 WHERE C# IN(SELECT C# FROM COURSE WHERE CNAME IN ('数据库', '企业管理', '英语'))
44
45 )
46
47 GROUP BY S#
48
49 )
50
51 );
18、 查询各科成绩最高和最低的分：以如下形式显示：课程ID，最高分，最低分；
View Code
1 SELECT C#, MAX(SCORE), MIN(SCORE) FROM SC GROUP BY C#;
19、 按各科平均成绩从低到高和及格率的百分数从高到低顺序；
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1 SELECT T1.C#, 2 3 ROUND(T1.AVG_SCORE, 2) AVG_SCORE, 4 5 ROUND(T2.PASS_COUNT / T1.ALL_COUNT, 2) PASS_POINT 6 7 FROM (SELECT DISTINCT C#, 8 9 COUNT(1) OVER(PARTITION BY C# ORDER BY C#) ALL_COUNT, 10 11 AVG(SCORE) OVER(PARTITION BY C# ORDER BY C#) AVG_SCORE 12 13 FROM SC) T1, 14 15 (SELECT DISTINCT C#, 16 17 COUNT(1) OVER(PARTITION BY C# ORDER BY C#) PASS_COUNT 18 19 FROM SC 20 21 WHERE SCORE >= 60) T2 22 23 WHERE T1.C# = T2.C# 24 25 ORDER BY AVG_SCORE, PASS_POINT DESC
20、 查询如下课程平均成绩和及格率的百分数: 企业管理（C#为001）平均分，企业管理及格百分数，马克思平（C#为002）均分，马克思及格百分数，UML（C#为003）平均分，UML及格百分数，数据库平均分（C#为004），数据库及格百分数
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1 WITH TT AS(
2
3 SELECT C#, SCORE
4
5 FROM SC
6
7 WHERE C# IN (SELECT C#
8
9 FROM COURSE
10
11 WHERE CNAME IN ('企业管理', '马列', 'UML', '数据库'))
12
13 )
14
15 SELECT T1.C#,
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17 ROUND(T1.AVG_SCORE, 2) AVG_SCORE,
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19 ROUND(T2.PASS_COUNT / T1.ALL_COUNT*100, 2) || '%' PASS_POINT
20
21 FROM (SELECT DISTINCT C#,
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23 COUNT(1) OVER(PARTITION BY C# ORDER BY C#) ALL_COUNT,
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25 AVG(SCORE) OVER(PARTITION BY C# ORDER BY C#) AVG_SCORE
26
27 FROM TT) T1,
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29 (SELECT DISTINCT C#,
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31 COUNT(1) OVER(PARTITION BY C# ORDER BY C#) PASS_COUNT
32
33 FROM TT
34
35 WHERE SCORE >= 60) T2
36
37 WHERE T1.C# = T2.C#
来源：https://www.cnblogs.com/baiyixianzi/archive/2012/08/19/sql1.html