1 /* 2 标题：一个项目涉及到的50个Sql语句(整理版) 3 作者：爱新觉罗.毓华(十八年风雨，守得冰山雪莲花开) 4 时间：2010-05-10 5 地点：重庆航天职业学院 6 说明：以下五十个语句都按照测试数据进行过测试，最好每次只单独运行一个语句。 7 问题及描述： 8 --1.学生表 9 Student(S#,Sname,Sage,Ssex) --S# 学生编号,Sname 学生姓名,Sage 出生年月,Ssex 学生性别 10 --2.课程表 11 Course(C#,Cname,T#) --C# --课程编号,Cname 课程名称,T# 教师编号 12 --3.教师表 13 Teacher(T#,Tname) --T# 教师编号,Tname 教师姓名 14 --4.成绩表 15 SC(S#,C#,score) --S# 学生编号,C# 课程编号,score 分数 16 */ 17 --创建测试数据 18 create table Student(S# varchar(10),Sname nvarchar(10),Sage datetime,Ssex nvarchar(10)) 19 insert into Student values('01' , N'赵雷' , '1990-01-01' , N'男') 20 insert into Student values('02' , N'钱电' , '1990-12-21' , N'男') 21 insert into Student values('03' , N'孙风' , '1990-05-20' , N'男') 22 insert into Student values('04' , N'李云' , '1990-08-06' , N'男') 23 insert into Student values('05' , N'周梅' , '1991-12-01' , N'女') 24 insert into Student values('06' , N'吴兰' , '1992-03-01' , N'女') 25 insert into Student values('07' , N'郑竹' , '1989-07-01' , N'女') 26 insert into Student values('08' , N'王菊' , '1990-01-20' , N'女') 27 create table Course(C# varchar(10),Cname nvarchar(10),T# varchar(10)) 28 insert into Course values('01' , N'语文' , '02') 29 insert into Course values('02' , N'数学' , '01') 30 insert into Course values('03' , N'英语' , '03') 31 create table Teacher(T# varchar(10),Tname nvarchar(10)) 32 insert into Teacher values('01' , N'张三') 33 insert into Teacher values('02' , N'李四') 34 insert into Teacher values('03' , N'王五') 35 create table SC(S# varchar(10),C# varchar(10),score decimal(18,1)) 36 insert into SC values('01' , '01' , 80) 37 insert into SC values('01' , '02' , 90) 38 insert into SC values('01' , '03' , 99) 39 insert into SC values('02' , '01' , 70) 40 insert into SC values('02' , '02' , 60) 41 insert into SC values('02' , '03' , 80) 42 insert into SC values('03' , '01' , 80) 43 insert into SC values('03' , '02' , 80) 44 insert into SC values('03' , '03' , 80) 45 insert into SC values('04' , '01' , 50) 46 insert into SC values('04' , '02' , 30) 47 insert into SC values('04' , '03' , 20) 48 insert into SC values('05' , '01' , 76) 49 insert into SC values('05' , '02' , 87) 50 insert into SC values('06' , '01' , 31) 51 insert into SC values('06' , '03' , 34) 52 insert into SC values('07' , '02' , 89) 53 insert into SC values('07' , '03' , 98) 54 go 55 56 --1、查询"01"课程比"02"课程成绩高的学生的信息及课程分数 57 --1.1、查询同时存在"01"课程和"02"课程的情况 58 select a.* , b.score [课程'01'的分数],c.score [课程'02'的分数] from Student a , SC b , SC c 59 where a.S# = b.S# and a.S# = c.S# and b.C# = '01' and c.C# = '02' and b.score > c.score 60 --1.2、查询同时存在"01"课程和"02"课程的情况和存在"01"课程但可能不存在"02"课程的情况(不存在时显示为null)(以下存在相同内容时不再解释) 61 select a.* , b.score [课程"01"的分数],c.score [课程"02"的分数] from Student a 62 left join SC b on a.S# = b.S# and b.C# = '01' 63 left join SC c on a.S# = c.S# and c.C# = '02' 64 where b.score > isnull(c.score,0) 65 66 --2、查询"01"课程比"02"课程成绩低的学生的信息及课程分数 67 --2.1、查询同时存在"01"课程和"02"课程的情况 68 select a.* , b.score [课程'01'的分数],c.score [课程'02'的分数] from Student a , SC b , SC c 69 where a.S# = b.S# and a.S# = c.S# and b.C# = '01' and c.C# = '02' and b.score < c.score 70 --2.2、查询同时存在"01"课程和"02"课程的情况和不存在"01"课程但存在"02"课程的情况 71 select a.* , b.score [课程"01"的分数],c.score [课程"02"的分数] from Student a 72 left join SC b on a.S# = b.S# and b.C# = '01' 73 left join SC c on a.S# = c.S# and c.C# = '02' 74 where isnull(b.score,0) < c.score 75 76 --3、查询平均成绩大于等于60分的同学的学生编号和学生姓名和平均成绩 77 select a.S# , a.Sname , cast(avg(b.score) as decimal(18,2)) avg_score 78 from Student a , sc b 79 where a.S# = b.S# 80 group by a.S# , a.Sname 81 having cast(avg(b.score) as decimal(18,2)) >= 60 82 order by a.S# 83 84 --4、查询平均成绩小于60分的同学的学生编号和学生姓名和平均成绩 85 --4.1、查询在sc表存在成绩的学生信息的SQL语句。 86 select a.S# , a.Sname , cast(avg(b.score) as decimal(18,2)) avg_score 87 from Student a , sc b 88 where a.S# = b.S# 89 group by a.S# , a.Sname 90 having cast(avg(b.score) as decimal(18,2)) < 60 91 order by a.S# 92 --4.2、查询在sc表中不存在成绩的学生信息的SQL语句。 93 select a.S# , a.Sname , isnull(cast(avg(b.score) as decimal(18,2)),0) avg_score 94 from Student a left join sc b 95 on a.S# = b.S# 96 group by a.S# , a.Sname 97 having isnull(cast(avg(b.score) as decimal(18,2)),0) < 60 98 order by a.S# 99 100 --5、查询所有同学的学生编号、学生姓名、选课总数、所有课程的总成绩 101 --5.1、查询所有有成绩的SQL。 102 select a.S# [学生编号], a.Sname [学生姓名], count(b.C#) 选课总数, sum(score) [所有课程的总成绩] 103 from Student a , SC b 104 where a.S# = b.S# 105 group by a.S#,a.Sname 106 order by a.S# 107 --5.2、查询所有(包括有成绩和无成绩)的SQL。 108 select a.S# [学生编号], a.Sname [学生姓名], count(b.C#) 选课总数, sum(score) [所有课程的总成绩] 109 from Student a left join SC b 110 on a.S# = b.S# 111 group by a.S#,a.Sname 112 order by a.S# 113 114 --6、查询"李"姓老师的数量 115 --方法1 116 select count(Tname) ["李"姓老师的数量] from Teacher where Tname like N'李%' 117 --方法2 118 select count(Tname) ["李"姓老师的数量] from Teacher where left(Tname,1) = N'李' 119 /* 120 "李"姓老师的数量 121 ----------- 122 1 123 */ 124 125 --7、查询学过"张三"老师授课的同学的信息 126 select distinct Student.* from Student , SC , Course , Teacher 127 where Student.S# = SC.S# and SC.C# = Course.C# and Course.T# = Teacher.T# and Teacher.Tname = N'张三' 128 order by Student.S# 129 130 --8、查询没学过"张三"老师授课的同学的信息 131 select m.* from Student m where S# not in (select distinct SC.S# from SC , Course , Teacher where SC.C# = Course.C# and Course.T# = Teacher.T# and Teacher.Tname = N'张三') order by m.S# 132 133 --9、查询学过编号为"01"并且也学过编号为"02"的课程的同学的信息 134 --方法1 135 select Student.* from Student , SC where Student.S# = SC.S# and SC.C# = '01' and exists (Select 1 from SC SC_2 where SC_2.S# = SC.S# and SC_2.C# = '02') order by Student.S# 136 --方法2 137 select Student.* from Student , SC where Student.S# = SC.S# and SC.C# = '02' and exists (Select 1 from SC SC_2 where SC_2.S# = SC.S# and SC_2.C# = '01') order by Student.S# 138 --方法3 139 select m.* from Student m where S# in 140 ( 141 select S# from 142 ( 143 select distinct S# from SC where C# = '01' 144 union all 145 select distinct S# from SC where C# = '02' 146 ) t group by S# having count(1) = 2 147 ) 148 order by m.S# 149 150 --10、查询学过编号为"01"但是没有学过编号为"02"的课程的同学的信息 151 --方法1 152 select Student.* from Student , SC where Student.S# = SC.S# and SC.C# = '01' and not exists (Select 1 from SC SC_2 where SC_2.S# = SC.S# and SC_2.C# = '02') order by Student.S# 153 --方法2 154 select Student.* from Student , SC where Student.S# = SC.S# and SC.C# = '01' and Student.S# not in (Select SC_2.S# from SC SC_2 where SC_2.S# = SC.S# and SC_2.C# = '02') order by Student.S# 155 156 --11、查询没有学全所有课程的同学的信息 157 --11.1、 158 select Student.* 159 from Student , SC 160 where Student.S# = SC.S# 161 group by Student.S# , Student.Sname , Student.Sage , Student.Ssex having count(C#) < (select count(C#) from Course) 162 --11.2 163 select Student.* 164 from Student left join SC 165 on Student.S# = SC.S# 166 group by Student.S# , Student.Sname , Student.Sage , Student.Ssex having count(C#) < (select count(C#) from Course) 167 168 --12、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 169 select distinct Student.* from Student , SC where Student.S# = SC.S# and SC.C# in (select C# from SC where S# = '01') and Student.S# <> '01' 170 171 --13、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 172 select Student.* from Student where S# in 173 (select distinct SC.S# from SC where S# <> '01' and SC.C# in (select distinct C# from SC where S# = '01') 174 group by SC.S# having count(1) = (select count(1) from SC where S#='01')) 175 176 --14、查询没学过"张三"老师讲授的任一门课程的学生姓名 177 select student.* from student where student.S# not in 178 (select distinct sc.S# from sc , course , teacher where sc.C# = course.C# and course.T# = teacher.T# and teacher.tname = N'张三') 179 order by student.S# 180 181 --15、查询两门及其以上不及格课程的同学的学号，姓名及其平均成绩 182 select student.S# , student.sname , cast(avg(score) as decimal(18,2)) avg_score from student , sc 183 where student.S# = SC.S# and student.S# in (select S# from SC where score < 60 group by S# having count(1) >= 2) 184 group by student.S# , student.sname 185 186 --16、检索"01"课程分数小于60，按分数降序排列的学生信息 187 select student.* , sc.C# , sc.score from student , sc 188 where student.S# = SC.S# and sc.score < 60 and sc.C# = '01' 189 order by sc.score desc 190 191 --17、按平均成绩从高到低显示所有学生的所有课程的成绩以及平均成绩 192 --17.1 SQL 2000 静态 193 select a.S# 学生编号 , a.Sname 学生姓名 , 194 max(case c.Cname when N'语文' then b.score else null end) [语文], 195 max(case c.Cname when N'数学' then b.score else null end) [数学], 196 max(case c.Cname when N'英语' then b.score else null end) [英语], 197 cast(avg(b.score) as decimal(18,2)) 平均分 198 from Student a 199 left join SC b on a.S# = b.S# 200 left join Course c on b.C# = c.C# 201 group by a.S# , a.Sname 202 order by 平均分 desc 203 --17.2 SQL 2000 动态 204 declare @sql nvarchar(4000) 205 set @sql = 'select a.S# ' + N'学生编号' + ' , a.Sname ' + N'学生姓名' 206 select @sql = @sql + ',max(case c.Cname when N'''+Cname+''' then b.score else null end) ['+Cname+']' 207 from (select distinct Cname from Course) as t 208 set @sql = @sql + ' , cast(avg(b.score) as decimal(18,2)) ' + N'平均分' + ' from Student a left join SC b on a.S# = b.S# left join Course c on b.C# = c.C# 209 group by a.S# , a.Sname order by ' + N'平均分' + ' desc' 210 exec(@sql) 211 --17.3 有关sql 2005的动静态写法参见我的文章《普通行列转换(version 2.0)》或《普通行列转换(version 3.0)》。 212 --18、查询各科成绩最高分、最低分和平均分：以如下形式显示：课程ID，课程name，最高分，最低分，平均分，及格率，中等率，优良率，优秀率 213 --及格为>=60，中等为：70-80，优良为：80-90，优秀为：>=90 214 --方法1 215 select m.C# [课程编号], m.Cname [课程名称], 216 max(n.score) [最高分], 217 min(n.score) [最低分], 218 cast(avg(n.score) as decimal(18,2)) [平均分], 219 cast((select count(1) from SC where C# = m.C# and score >= 60)*100.0 / (select count(1) from SC where C# = m.C#) as decimal(18,2)) [及格率(%)], 220 cast((select count(1) from SC where C# = m.C# and score >= 70 and score < 80 )*100.0 / (select count(1) from SC where C# = m.C#) as decimal(18,2)) [中等率(%)], 221 cast((select count(1) from SC where C# = m.C# and score >= 80 and score < 90 )*100.0 / (select count(1) from SC where C# = m.C#) as decimal(18,2)) [优良率(%)], 222 cast((select count(1) from SC where C# = m.C# and score >= 90)*100.0 / (select count(1) from SC where C# = m.C#) as decimal(18,2)) [优秀率(%)] 223 from Course m , SC n 224 where m.C# = n.C# 225 group by m.C# , m.Cname 226 order by m.C# 227 --方法2 228 select m.C# [课程编号], m.Cname [课程名称], 229 (select max(score) from SC where C# = m.C#) [最高分], 230 (select min(score) from SC where C# = m.C#) [最低分], 231 (select cast(avg(score) as decimal(18,2)) from SC where C# = m.C#) [平均分], 232 cast((select count(1) from SC where C# = m.C# and score >= 60)*100.0 / (select count(1) from SC where C# = m.C#) as decimal(18,2)) [及格率(%)], 233 cast((select count(1) from SC where C# = m.C# and score >= 70 and score < 80 )*100.0 / (select count(1) from SC where C# = m.C#) as decimal(18,2)) [中等率(%)], 234 cast((select count(1) from SC where C# = m.C# and score >= 80 and score < 90 )*100.0 / (select count(1) from SC where C# = m.C#) as decimal(18,2)) [优良率(%)], 235 cast((select count(1) from SC where C# = m.C# and score >= 90)*100.0 / (select count(1) from SC where C# = m.C#) as decimal(18,2)) [优秀率(%)] 236 from Course m 237 order by m.C# 238 239 --19、按各科成绩进行排序，并显示排名 240 --19.1 sql 2000用子查询完成 241 --Score重复时保留名次空缺 242 select t.* , px = (select count(1) from SC where C# = t.C# and score > t.score) + 1 from sc t order by t.c# , px 243 --Score重复时合并名次 244 select t.* , px = (select count(distinct score) from SC where C# = t.C# and score >= t.score) from sc t order by t.c# , px 245 --19.2 sql 2005用rank,DENSE_RANK完成 246 --Score重复时保留名次空缺(rank完成) 247 select t.* , px = rank() over(partition by c# order by score desc) from sc t order by t.C# , px 248 --Score重复时合并名次(DENSE_RANK完成) 249 select t.* , px = DENSE_RANK() over(partition by c# order by score desc) from sc t order by t.C# , px 250 251 --20、查询学生的总成绩并进行排名 252 --20.1 查询学生的总成绩 253 select m.S# [学生编号] , 254 m.Sname [学生姓名] , 255 isnull(sum(score),0) [总成绩] 256 from Student m left join SC n on m.S# = n.S# 257 group by m.S# , m.Sname 258 order by [总成绩] desc 259 --20.2 查询学生的总成绩并进行排名，sql 2000用子查询完成，分总分重复时保留名次空缺和不保留名次空缺两种。 260 select t1.* , px = (select count(1) from 261 ( 262 select m.S# [学生编号] , 263 m.Sname [学生姓名] , 264 isnull(sum(score),0) [总成绩] 265 from Student m left join SC n on m.S# = n.S# 266 group by m.S# , m.Sname 267 ) t2 where 总成绩 > t1.总成绩) + 1 from 268 ( 269 select m.S# [学生编号] , 270 m.Sname [学生姓名] , 271 isnull(sum(score),0) [总成绩] 272 from Student m left join SC n on m.S# = n.S# 273 group by m.S# , m.Sname 274 ) t1 275 order by px 276 277 select t1.* , px = (select count(distinct 总成绩) from 278 ( 279 select m.S# [学生编号] , 280 m.Sname [学生姓名] , 281 isnull(sum(score),0) [总成绩] 282 from Student m left join SC n on m.S# = n.S# 283 group by m.S# , m.Sname 284 ) t2 where 总成绩 >= t1.总成绩) from 285 ( 286 select m.S# [学生编号] , 287 m.Sname [学生姓名] , 288 isnull(sum(score),0) [总成绩] 289 from Student m left join SC n on m.S# = n.S# 290 group by m.S# , m.Sname 291 ) t1 292 order by px 293 --20.3 查询学生的总成绩并进行排名，sql 2005用rank,DENSE_RANK完成，分总分重复时保留名次空缺和不保留名次空缺两种。 294 select t.* , px = rank() over(order by [总成绩] desc) from 295 ( 296 select m.S# [学生编号] , 297 m.Sname [学生姓名] , 298 isnull(sum(score),0) [总成绩] 299 from Student m left join SC n on m.S# = n.S# 300 group by m.S# , m.Sname 301 ) t 302 order by px 303 304 select t.* , px = DENSE_RANK() over(order by [总成绩] desc) from 305 ( 306 select m.S# [学生编号] , 307 m.Sname [学生姓名] , 308 isnull(sum(score),0) [总成绩] 309 from Student m left join SC n on m.S# = n.S# 310 group by m.S# , m.Sname 311 ) t 312 order by px 313 314 --21、查询不同老师所教不同课程平均分从高到低显示 315 select m.T# , m.Tname , cast(avg(o.score) as decimal(18,2)) avg_score 316 from Teacher m , Course n , SC o 317 where m.T# = n.T# and n.C# = o.C# 318 group by m.T# , m.Tname 319 order by avg_score desc 320 321 --22、查询所有课程的成绩第2名到第3名的学生信息及该课程成绩 322 --22.1 sql 2000用子查询完成 323 --Score重复时保留名次空缺 324 select * from (select t.* , px = (select count(1) from SC where C# = t.C# and score > t.score) + 1 from sc t) m where px between 2 and 3 order by m.c# , m.px 325 --Score重复时合并名次 326 select * from (select t.* , px = (select count(distinct score) from SC where C# = t.C# and score >= t.score) from sc t) m where px between 2 and 3 order by m.c# , m.px 327 --22.2 sql 2005用rank,DENSE_RANK完成 328 --Score重复时保留名次空缺(rank完成) 329 select * from (select t.* , px = rank() over(partition by c# order by score desc) from sc t) m where px between 2 and 3 order by m.C# , m.px 330 --Score重复时合并名次(DENSE_RANK完成) 331 select * from (select t.* , px = DENSE_RANK() over(partition by c# order by score desc) from sc t) m where px between 2 and 3 order by m.C# , m.px 332 333 --23、统计各科成绩各分数段人数：课程编号,课程名称,[100-85],[85-70],[70-60],[0-60]及所占百分比 334 --23.1 统计各科成绩各分数段人数：课程编号,课程名称,[100-85],[85-70],[70-60],[0-60] 335 --横向显示 336 select Course.C# [课程编号] , Cname as [课程名称] , 337 sum(case when score >= 85 then 1 else 0 end) [85-100], 338 sum(case when score >= 70 and score < 85 then 1 else 0 end) [70-85], 339 sum(case when score >= 60 and score < 70 then 1 else 0 end) [60-70], 340 sum(case when score < 60 then 1 else 0 end) [0-60] 341 from sc , Course 342 where SC.C# = Course.C# 343 group by Course.C# , Course.Cname 344 order by Course.C# 345 --纵向显示1(显示存在的分数段) 346 select m.C# [课程编号] , m.Cname [课程名称] , 分数段 = ( 347 case when n.score >= 85 then '85-100' 348 when n.score >= 70 and n.score < 85 then '70-85' 349 when n.score >= 60 and n.score < 70 then '60-70' 350 else '0-60' 351 end) , 352 count(1) 数量 353 from Course m , sc n 354 where m.C# = n.C# 355 group by m.C# , m.Cname , ( 356 case when n.score >= 85 then '85-100' 357 when n.score >= 70 and n.score < 85 then '70-85' 358 when n.score >= 60 and n.score < 70 then '60-70' 359 else '0-60' 360 end) 361 order by m.C# , m.Cname , 分数段 362 --纵向显示2(显示存在的分数段，不存在的分数段用0显示) 363 select m.C# [课程编号] , m.Cname [课程名称] , 分数段 = ( 364 case when n.score >= 85 then '85-100' 365 when n.score >= 70 and n.score < 85 then '70-85' 366 when n.score >= 60 and n.score < 70 then '60-70' 367 else '0-60' 368 end) , 369 count(1) 数量 370 from Course m , sc n 371 where m.C# = n.C# 372 group by all m.C# , m.Cname , ( 373 case when n.score >= 85 then '85-100' 374 when n.score >= 70 and n.score < 85 then '70-85' 375 when n.score >= 60 and n.score < 70 then '60-70' 376 else '0-60' 377 end) 378 order by m.C# , m.Cname , 分数段 379 380 --23.2 统计各科成绩各分数段人数：课程编号,课程名称,[100-85],[85-70],[70-60],[<60]及所占百分比 381 --横向显示 382 select m.C# 课程编号, m.Cname 课程名称, 383 (select count(1) from SC where C# = m.C# and score < 60) [0-60], 384 cast((select count(1) from SC where C# = m.C# and score < 60)*100.0 / (select count(1) from SC where C# = m.C#) as decimal(18,2)) [百分比(%)], 385 (select count(1) from SC where C# = m.C# and score >= 60 and score < 70) [60-70], 386 cast((select count(1) from SC where C# = m.C# and score >= 60 and score < 70)*100.0 / (select count(1) from SC where C# = m.C#) as decimal(18,2)) [百分比(%)], 387 (select count(1) from SC where C# = m.C# and score >= 70 and score < 85) [70-85], 388 cast((select count(1) from SC where C# = m.C# and score >= 70 and score < 85)*100.0 / (select count(1) from SC where C# = m.C#) as decimal(18,2)) [百分比(%)], 389 (select count(1) from SC where C# = m.C# and score >= 85) [85-100], 390 cast((select count(1) from SC where C# = m.C# and score >= 85)*100.0 / (select count(1) from SC where C# = m.C#) as decimal(18,2)) [百分比(%)] 391 from Course m 392 order by m.C# 393 --纵向显示1(显示存在的分数段) 394 select m.C# [课程编号] , m.Cname [课程名称] , 分数段 = ( 395 case when n.score >= 85 then '85-100' 396 when n.score >= 70 and n.score < 85 then '70-85' 397 when n.score >= 60 and n.score < 70 then '60-70' 398 else '0-60' 399 end) , 400 count(1) 数量 , 401 cast(count(1) * 100.0 / (select count(1) from sc where C# = m.C#) as decimal(18,2)) [百分比(%)] 402 from Course m , sc n 403 where m.C# = n.C# 404 group by m.C# , m.Cname , ( 405 case when n.score >= 85 then '85-100' 406 when n.score >= 70 and n.score < 85 then '70-85' 407 when n.score >= 60 and n.score < 70 then '60-70' 408 else '0-60' 409 end) 410 order by m.C# , m.Cname , 分数段 411 --纵向显示2(显示存在的分数段，不存在的分数段用0显示) 412 select m.C# [课程编号] , m.Cname [课程名称] , 分数段 = ( 413 case when n.score >= 85 then '85-100' 414 when n.score >= 70 and n.score < 85 then '70-85' 415 when n.score >= 60 and n.score < 70 then '60-70' 416 else '0-60' 417 end) , 418 count(1) 数量 , 419 cast(count(1) * 100.0 / (select count(1) from sc where C# = m.C#) as decimal(18,2)) [百分比(%)] 420 from Course m , sc n 421 where m.C# = n.C# 422 group by all m.C# , m.Cname , ( 423 case when n.score >= 85 then '85-100' 424 when n.score >= 70 and n.score < 85 then '70-85' 425 when n.score >= 60 and n.score < 70 then '60-70' 426 else '0-60' 427 end) 428 order by m.C# , m.Cname , 分数段 429 430 --24、查询学生平均成绩及其名次 431 --24.1 查询学生的平均成绩并进行排名，sql 2000用子查询完成，分平均成绩重复时保留名次空缺和不保留名次空缺两种。 432 select t1.* , px = (select count(1) from 433 ( 434 select m.S# [学生编号] , 435 m.Sname [学生姓名] , 436 isnull(cast(avg(score) as decimal(18,2)),0) [平均成绩] 437 from Student m left join SC n on m.S# = n.S# 438 group by m.S# , m.Sname 439 ) t2 where 平均成绩 > t1.平均成绩) + 1 from 440 ( 441 select m.S# [学生编号] , 442 m.Sname [学生姓名] , 443 isnull(cast(avg(score) as decimal(18,2)),0) [平均成绩] 444 from Student m left join SC n on m.S# = n.S# 445 group by m.S# , m.Sname 446 ) t1 447 order by px 448 449 select t1.* , px = (select count(distinct 平均成绩) from 450 ( 451 select m.S# [学生编号] , 452 m.Sname [学生姓名] , 453 isnull(cast(avg(score) as decimal(18,2)),0) [平均成绩] 454 from Student m left join SC n on m.S# = n.S# 455 group by m.S# , m.Sname 456 ) t2 where 平均成绩 >= t1.平均成绩) from 457 ( 458 select m.S# [学生编号] , 459 m.Sname [学生姓名] , 460 isnull(cast(avg(score) as decimal(18,2)),0) [平均成绩] 461 from Student m left join SC n on m.S# = n.S# 462 group by m.S# , m.Sname 463 ) t1 464 order by px 465 --24.2 查询学生的平均成绩并进行排名，sql 2005用rank,DENSE_RANK完成，分平均成绩重复时保留名次空缺和不保留名次空缺两种。 466 select t.* , px = rank() over(order by [平均成绩] desc) from 467 ( 468 select m.S# [学生编号] , 469 m.Sname [学生姓名] , 470 isnull(cast(avg(score) as decimal(18,2)),0) [平均成绩] 471 from Student m left join SC n on m.S# = n.S# 472 group by m.S# , m.Sname 473 ) t 474 order by px 475 476 select t.* , px = DENSE_RANK() over(order by [平均成绩] desc) from 477 ( 478 select m.S# [学生编号] , 479 m.Sname [学生姓名] , 480 isnull(cast(avg(score) as decimal(18,2)),0) [平均成绩] 481 from Student m left join SC n on m.S# = n.S# 482 group by m.S# , m.Sname 483 ) t 484 order by px 485 486 --25、查询各科成绩前三名的记录 487 --25.1 分数重复时保留名次空缺 488 select m.* , n.C# , n.score from Student m, SC n where m.S# = n.S# and n.score in 489 (select top 3 score from sc where C# = n.C# order by score desc) order by n.C# , n.score desc 490 --25.2 分数重复时不保留名次空缺，合并名次 491 --sql 2000用子查询实现 492 select * from (select t.* , px = (select count(distinct score) from SC where C# = t.C# and score >= t.score) from sc t) m where px between 1 and 3 order by m.c# , m.px 493 --sql 2005用DENSE_RANK实现 494 select * from (select t.* , px = DENSE_RANK() over(partition by c# order by score desc) from sc t) m where px between 1 and 3 order by m.C# , m.px 495 496 --26、查询每门课程被选修的学生数 497 select c# , count(S#)[学生数] from sc group by C# 498 499 --27、查询出只有两门课程的全部学生的学号和姓名 500 select Student.S# , Student.Sname 501 from Student , SC 502 where Student.S# = SC.S# 503 group by Student.S# , Student.Sname 504 having count(SC.C#) = 2 505 order by Student.S# 506 507 --28、查询男生、女生人数 508 select count(Ssex) as 男生人数 from Student where Ssex = N'男' 509 select count(Ssex) as 女生人数 from Student where Ssex = N'女' 510 select sum(case when Ssex = N'男' then 1 else 0 end) [男生人数],sum(case when Ssex = N'女' then 1 else 0 end) [女生人数] from student 511 select case when Ssex = N'男' then N'男生人数' else N'女生人数' end [男女情况] , count(1) [人数] from student group by case when Ssex = N'男' then N'男生人数' else N'女生人数' end 512 513 --29、查询名字中含有"风"字的学生信息 514 select * from student where sname like N'%风%' 515 select * from student where charindex(N'风' , sname) > 0 516 517 --30、查询同名同性学生名单，并统计同名人数 518 select Sname [学生姓名], count(*) [人数] from Student group by Sname having count(*) > 1 519 520 --31、查询1990年出生的学生名单(注：Student表中Sage列的类型是datetime) 521 select * from Student where year(sage) = 1990 522 select * from Student where datediff(yy,sage,'1990-01-01') = 0 523 select * from Student where datepart(yy,sage) = 1990 524 select * from Student where convert(varchar(4),sage,120) = '1990' 525 526 --32、查询每门课程的平均成绩，结果按平均成绩降序排列，平均成绩相同时，按课程编号升序排列 527 select m.C# , m.Cname , cast(avg(n.score) as decimal(18,2)) avg_score 528 from Course m, SC n 529 where m.C# = n.C# 530 group by m.C# , m.Cname 531 order by avg_score desc, m.C# asc 532 533 --33、查询平均成绩大于等于85的所有学生的学号、姓名和平均成绩 534 select a.S# , a.Sname , cast(avg(b.score) as decimal(18,2)) avg_score 535 from Student a , sc b 536 where a.S# = b.S# 537 group by a.S# , a.Sname 538 having cast(avg(b.score) as decimal(18,2)) >= 85 539 order by a.S# 540 541 --34、查询课程名称为"数学"，且分数低于60的学生姓名和分数 542 select sname , score 543 from Student , SC , Course 544 where SC.S# = Student.S# and SC.C# = Course.C# and Course.Cname = N'数学' and score < 60 545 546 --35、查询所有学生的课程及分数情况； 547 select Student.* , Course.Cname , SC.C# , SC.score 548 from Student, SC , Course 549 where Student.S# = SC.S# and SC.C# = Course.C# 550 order by Student.S# , SC.C# 551 552 --36、查询任何一门课程成绩在70分以上的姓名、课程名称和分数； 553 select Student.* , Course.Cname , SC.C# , SC.score 554 from Student, SC , Course 555 where Student.S# = SC.S# and SC.C# = Course.C# and SC.score >= 70 556 order by Student.S# , SC.C# 557 558 --37、查询不及格的课程 559 select Student.* , Course.Cname , SC.C# , SC.score 560 from Student, SC , Course 561 where Student.S# = SC.S# and SC.C# = Course.C# and SC.score < 60 562 order by Student.S# , SC.C# 563 564 --38、查询课程编号为01且课程成绩在80分以上的学生的学号和姓名； 565 select Student.* , Course.Cname , SC.C# , SC.score 566 from Student, SC , Course 567 where Student.S# = SC.S# and SC.C# = Course.C# and SC.C# = '01' and SC.score >= 80 568 order by Student.S# , SC.C# 569 570 --39、求每门课程的学生人数 571 select Course.C# , Course.Cname , count(*) [学生人数] 572 from Course , SC 573 where Course.C# = SC.C# 574 group by Course.C# , Course.Cname 575 order by Course.C# , Course.Cname 576 577 --40、查询选修"张三"老师所授课程的学生中，成绩最高的学生信息及其成绩 578 --40.1 当最高分只有一个时 579 select top 1 Student.* , Course.Cname , SC.C# , SC.score 580 from Student, SC , Course , Teacher 581 where Student.S# = SC.S# and SC.C# = Course.C# and Course.T# = Teacher.T# and Teacher.Tname = N'张三' 582 order by SC.score desc 583 --40.2 当最高分出现多个时 584 select Student.* , Course.Cname , SC.C# , SC.score 585 from Student, SC , Course , Teacher 586 where Student.S# = SC.S# and SC.C# = Course.C# and Course.T# = Teacher.T# and Teacher.Tname = N'张三' and 587 SC.score = (select max(SC.score) from SC , Course , Teacher where SC.C# = Course.C# and Course.T# = Teacher.T# and Teacher.Tname = N'张三') 588 589 --41、查询不同课程成绩相同的学生的学生编号、课程编号、学生成绩 590 --方法1 591 select m.* from SC m ,(select C# , score from SC group by C# , score having count(1) > 1) n 592 where m.C#= n.C# and m.score = n.score order by m.C# , m.score , m.S# 593 --方法2 594 select m.* from SC m where exists (select 1 from (select C# , score from SC group by C# , score having count(1) > 1) n 595 where m.C#= n.C# and m.score = n.score) order by m.C# , m.score , m.S# 596 597 --42、查询每门功成绩最好的前两名 598 select t.* from sc t where score in (select top 2 score from sc where C# = T.C# order by score desc) order by t.C# , t.score desc 599 600 --43、统计每门课程的学生选修人数（超过5人的课程才统计）。要求输出课程号和选修人数，查询结果按人数降序排列，若人数相同，按课程号升序排列 601 select Course.C# , Course.Cname , count(*) [学生人数] 602 from Course , SC 603 where Course.C# = SC.C# 604 group by Course.C# , Course.Cname 605 having count(*) >= 5 606 order by [学生人数] desc , Course.C# 607 608 --44、检索至少选修两门课程的学生学号 609 select student.S# , student.Sname 610 from student , SC 611 where student.S# = SC.S# 612 group by student.S# , student.Sname 613 having count(1) >= 2 614 order by student.S# 615 616 --45、查询选修了全部课程的学生信息 617 --方法1 根据数量来完成 618 select student.* from student where S# in 619 (select S# from sc group by S# having count(1) = (select count(1) from course)) 620 --方法2 使用双重否定来完成 621 select t.* from student t where t.S# not in 622 ( 623 select distinct m.S# from 624 ( 625 select S# , C# from student , course 626 ) m where not exists (select 1 from sc n where n.S# = m.S# and n.C# = m.C#) 627 ) 628 --方法3 使用双重否定来完成 629 select t.* from student t where not exists(select 1 from 630 ( 631 select distinct m.S# from 632 ( 633 select S# , C# from student , course 634 ) m where not exists (select 1 from sc n where n.S# = m.S# and n.C# = m.C#) 635 ) k where k.S# = t.S# 636 ) 637 638 --46、查询各学生的年龄 639 --46.1 只按照年份来算 640 select * , datediff(yy , sage , getdate()) [年龄] from student 641 --46.2 按照出生日期来算，当前月日 < 出生年月的月日则，年龄减一 642 select * , case when right(convert(varchar(10),getdate(),120),5) < right(convert(varchar(10),sage,120),5) then datediff(yy , sage , getdate()) - 1 else datediff(yy , sage , getdate()) end [年龄] from student 643 644 --47、查询本周过生日的学生 645 select * from student where datediff(week,datename(yy,getdate()) + right(convert(varchar(10),sage,120),6),getdate()) = 0 646 647 --48、查询下周过生日的学生 648 select * from student where datediff(week,datename(yy,getdate()) + right(convert(varchar(10),sage,120),6),getdate()) = -1 649 650 --49、查询本月过生日的学生 651 select * from student where datediff(mm,datename(yy,getdate()) + right(convert(varchar(10),sage,120),6),getdate()) = 0 652 653 --50、查询下月过生日的学生 654 select * from student where datediff(mm,datename(yy,getdate()) + right(convert(varchar(10),sage,120),6),getdate()) = -1 655 656 drop table Student,Course,Teacher,SC