这是MySQL的基本操作：
  1 登入数据库：mysql -uroot -p+密码 (SQL Sever登入： osql  -U 用户名  -P 密码)
  2 显示已存在的数据库：show databases;
  3 使用某个数据库：use+数据库名;
  4 显示某个数据库下已存在的关系表：show tables;
  5 
  6 查看某个关系表所有数据：select * from tableName;
  7 查看某个关系表部分字段数据：select 字段1，字段2，...，字段n from tableName;
  8 查看n条记录：select ... from ... limit n;
  9 查看第i条到第j条之间的记录：select ... from ... limit i,j;
 10 
 11 使用order by 来对记录进行排序，默认从小到大
 12 >select stuName, stuScore from student order by stuScore desc;  //（从大到小）
 13 >select stuName, stuScore from student order by stuScore asc;   //（从小到大）
 14 
 15 去重: distinct
 16 >select distinct stuCourse from student;
 17 > select count(distinct stuCourse) from student;
 18 
 19 
 20 聚合函数(常用于GROUP BY从句的SELECT查询中)
 21 AVG(col)返回指定列的平均值
 22 COUNT(col)返回指定列中非NULL值的个数
 23 MIN(col)返回指定列的最小值
 24 MAX(col)返回指定列的最大值
 25 SUM(col)返回指定列的所有值之和
 26 GROUP_CONCAT(col) 返回由属于一组的列值连接组合而成的结果
 27 > select stuCourse, sum(stuScore) from student where stuCourse = "Chinese";
 28 > select stuCourse, sum(stuScore) from student group by stuCourse;
 29 > select stuCourse, avg(stuScore) from student group by stuCourse;
 30 > select stuCourse, max(stuScore) from student group by stuCourse;
 31 > select stuCourse, min(stuScore) from student group by stuCourse;
 32 > select avg(stuAge) as avg_age from student;
 33 > select group_concat(stuName, stuCourse) from student;
 34 
 35 条件限制：where : =, !=, >, >=, <, <=, and, not, or
 36          , between...and..., not between...and...
 37          , is null, is not null, like(%, _), not like(%, _)
 38          , in(项1, 项2, …), not in(项1, 项2, …)
 39          , exists, not exists
 40          , any, some, all
 41 
 42 %: 匹配任意个字符
 43 _：匹配单个字符
 44 
 45 创建数据库：create database 数据库名;
 46 创建关系表：create table tableName(字段1 类型 限制，字段2 类型 限制，...,字段n 类型 限制);
 47 显示关系表的格式：show create table tableName;
 48 更新数据：update tableName set 字段1 = 字段1值, 字段2 = 字段2值, ..., 字段n = 字段n值;
 49 
 50 插入数据：insert tableName(字段1，字段2，...，字段n) values(字段1值，字段2值，...，字段n值);
 51 
 52 生成一个关系表的备份：create table baktableName (select * from tableName);
 53 使用备份的数据对新表插入数据
 54 > insert book select * from bookBak;
 55 
 56 生成一个数据库的备份：mysqldump -uUserName -p dbname > bakefile;
 57 使用数据库的备份恢复数据库：mysql -uUserName -p dbname < bakefile;
 58 
 59 使用交互方式恢复数据库：
 60 > create database dbName; (如果不存在这个数据库)
 61 > use dbName;
 62 > source bakeFile;
 63 
 64 删除一个数据库：drop database dbname;
 65 删除关系表中所有数据：delete from tableName;    
 66 删除关系表中符合条件的数据：delete from tableName where...;
 67 
 68 给关系表增加一个字段：alter table tableName add 字段名 说明(default ‘H‘);
 69 给关系表删除一个字段：alter table tableName drop 字段名;
 70 给关系表修改一个字段：alter table tableName modify 字段名 说明;
 71 给关系表修改一个字段：alter table tableName change 旧字段名 新字段名 说明(类型...);
 72 
 73 设置字段值唯一，即该字段的值不允许有重复的: unique
 74 > create table tmp(id int unique not null, name varchar(32));
 75 
 76 主键：唯一标识一条记录，主键可以是单个字段，也可以是多个字段合成的
 77 > alter table student modify stuId varchar(32) primary key not null;
 78 
 79 > create table book(bookId bigint auto_increment primary key not null, bookName varchar(32) not null);
 80 > create table book(bookId bigint auto_increment not null, bookName varchar(32) not null, primary key(bookId));
 81 
 82 > create table score(stuId varchar(32) not null, 
 83 > bookId bigInt not null,
 84 > score float,
 85 > primary key(stuId, bookId));
 86 
 87 多表查询
 88 > select score.bookId, stuName, bookName from score, student, book where score.bookId = book.bookId and score.stuId = student.stuId;
 89 > select score.bookId, stuName, bookName, score from score, student, book where score.bookId = book.bookId and score.stuId = student.stuId;
 90 
 91 外键
 92 > alter table score add constraint stuId_cons foreign key(stuId) references student(stuId);
 93 > alter table score add constraint bookId_cons foreign key(bookId) references book(bookId);
 94 
 95 > create table tecbook(tecId varchar(32) not null, bookId bigint not null, primary key(tecId, bookId), foreign key(tecId) references teacher(tecId), foreign key(bookId) references book(bookId));
 96 
 97 
 98 
 99 学生表student(stuId,stuName,stuAge,stuSex) 
100 mysql> create table student(stuId varchar(32) primary key not null,
101     -> stuName varchar(32) not null,
102     -> stuAge int,
103     -> stuSex char);
104 
105 教师表 teacher(tecId,tecName) 
106 mysql> create table teacher(tecId varchar(32) primary key not null,
107     -> tecName varchar(32) not null);
108 
109 课程表course(courseId,courseName,tecId) 
110 mysql> create table course(courseId bigint primary key auto_increment not null,
111     -> courseName varchar(32) not null,
112     -> tecId varchar(32) not null,
113     -> foreign key(tecId) references teacher(tecId) on update cascade on delete cascade);
114 
115 成绩表score(stuId,courseId,score,note) 
116 mysql> create table score(stuId varchar(32) not null,
117     -> courseId bigint not null,
118     -> score float,
119     -> note varchar(64),
120     -> primary key(stuId, courseId),
121     -> foreign key(stuId) references student(stuId) on delete cascade on update cascade,
122     -> foreign key(courseId) references course(courseId) on delete no action on update cascade);
123 
124 
125 级联操作：
126     foreign key(column) references tableName(column) 
127     [[on delete | on update] [cascade | no action | set null | restrict]];
128 
129 
130 查询每个学生每门课的成绩
131 > select stuName, courseName, score from student, course, score where student.stuId = score.stuId 
132   and course.courseId = score.courseId;
133 
134 查询每个学生的总成绩
135 > select stuName, sum(score) from student, course, score where student.stuId = score.stuId 
136   and course.courseId = score.courseId group by stuName;
137 
138 对每个学生的总成绩排序
139 > select stuName, sum(score) as sum_score from student, course, score where student.stuId = score.stuId 
140   and course.courseId = score.courseId group by stuName order by sum_score desc;
141 
142 查询每个学生的平均成绩
143 > select stuName, avg(score) from student, course, score where student.stuId = score.stuId 
144   and course.courseId = score.courseId group by stuName;
145 
146 查询平均成绩>80的学生
147 > select stuName, avg(score) as avg_score from student, course, score where student.stuId = score.stuId and course.courseId = score.courseId group by stuName having avg_score > 80;
148 Note: having字句可以让我们筛选成组后的各种数据，where字句在聚合前先筛选记录，也就是说作用在group by和having字句前。而 having子句在聚合后对组记录进行筛选。
149 
150 查询“3004”课程比“3002”课程成绩高的所有学生的学号
151 > select t1.stuId from (select stuId, score from score where courseId = 3002) as t1, 
152   (select stuId, score from score where courseId = 3004) as t2 where t1.score < t2.score 
153   and t1.stuId = t2.stuId;
154 
155 > select stuId from score s1 where courseId = 3002 and score < 
156   (select score from score s2 where courseId  = 3004 and s1.stuId = s2.stuId);
157 
158 > select s1.stuId from score s1, score s2 where s1.score < s2.score and s1.stuId = s2.stuId 
159   and s1.courseId = 3002 and s2.courseId = 3004;
160 
161 查询所有同学的学号、姓名、课数、总成绩
162 > select score.stuId, stuName, count(courseId) as course_num, sum(score)  as sum_score from score, student where score.stuId = student.stuId group by stuId;
163 
164 查询和likui性别相同的学生信息
165 > select stuId, stuName from student where stuSex = (select stuSex from student where stuName = "likui") 
166   and stuName != "likui";
167 
168 查询没学过“mozi”老师课的同学的学号、姓名
169 > select distinct score.stuId, stuName from score, student where score.stuId = student.stuId 
170   and score.stuId != 
171       (
172           select stuId from score where courseId in 
173           (
174               select courseId from course where tecId = 
175               (select tecId from teacher where tecName = "mozi")
176           )
177       );
178 
179 查询每个老师所教课程平均分从高到低显示
180 > select c.courseId, c.courseName, avg(sc.score) avgScore, t.tecName from course c, score sc, teacher t  where c.courseId = sc.courseId and c.tecId = t.tecId group by(sc.courseId) order by avgScore DESC;
181 
182 > select course.tecId, teacher.tecName, t1.courseId, t1.avg_score from (select courseId, avg(score) as avg_score from score group by courseId) as t1, course, teacher where t1.courseId = course.courseId and course.tecId = teacher.tecId;
183 
184 删除学习“laozi”老师课的score表记录
185 > delete from score where courseId in (select courseId from course 
186   where tecId = (select tecId from teacher where tecName = "laozi"));
187 
188 查询两门及以上不及格课程的同学的学号及其平均成绩
189 > select stuId, avg(score) from score where stuId in (select stuId from score  where score < 60  group by stuId having count(*) >= 2) group by stuId;
190 
191 > select stuId, avg(score) from score where stuId in (select stuId from (select stuId, count(*) as blow from score  where score < 60  group by stuId having blow >= 2)as t1) group by stuId;
192 
193 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
194 > select courseId, max(score), min(score) from score group by courseId;    
195 
196 查询学过“3001”并且也学过编号“3003”课程的同学的学号、姓名
197 > select stuId, stuName from student where stuId in (select s1.stuId from score s1, score s2 where s1.courseId = 3001 and s2.courseId = 3003 and s1.stuId = s2.stuId);
198 
199 查询“3001”课程的分数比“3001”课程平均分低的学生stuId, stuName
200 > select stuId, stuName from student where stuId in(select stuId from score where score < (select avg(score) from score where courseId = 3001) and courseId = 3001);
201 
202 查询“3001”课程的分数比“3001”课程平均分低的学生stuId, stuName, score
203 > select score.stuId, stuName, score from score, student where score < (select avg(score) from score 
204   where courseId = 3001) and courseId = 3001 and score.stuId = student.stuId;
205 
206 查询“3001”课程的分数比“3001”课程平均分低的学生stuId, stuName, score, avg_score
207 > select score.stuId, stuName, (select avg(score) from score where courseId = 3001) as avg_score, score from score, student where score < (select avg(score) from score where courseId = 3001) and courseId = 3001 and score.stuId = student.stuId;
208 
209 
210 view: 是视图，是一张虚表，表中没有任何数据
211 > create view score_view as select score.stuId, stuName, count(courseId) as course_num, sum(score)  as sum_score from score, student where score.stuId = student.stuId group by stuId;
212 
213 > select * from score_view;
214 
215 存储过程：
216 delimiter $$
217 create procedure proName(in | out | inout)
218 begin
219 commands;
220 end
221 $$
222 
223 
224 mysql> delimiter //
225 mysql> create procedure pro_new()
226     -> begin
227     -> select * from student;
228     -> select * from course;
229     -> select * from teacher;
230     -> end
231     -> //
232 mysql> delimiter ;
233 mysql> call pro_new;
234 
235 
236 
237 mysql> delimiter //
238 mysql> create procedure addTec(in id varchar(32), in name varchar(32))
239     -> begin
240     -> insert teacher(tecId, tecName) values(id, name);
241     -> end
242     -> //
243 
244 mysql> delimiter ;
245 mysql> call addTec("2010", "daai");
246 
247 
248 mysql> delimiter //
249 mysql> create procedure pp(out op int)
250     -> begin
251     -> set op = 90;
252     -> end
253     -> //
254 
255 mysql> delimiter ;
256 mysql> set @opp = 0;
257 mysql> select @opp;
258 mysql> call pp(@opp);
259 mysql> select @opp;
260 
261 
262 1, if-then-else 分支
263 if condition then
264     commands;
265 [elseif condition then
266     commands;]
267 [else
268     commands;]
269 end if;
270 
271 mysql> delimiter //
272 mysql> create procedure sala_pro4(in level int) 
273      > begin 
274      > if level = 2 then 
275      >     update teacher set tecSalary = 5000 where tecLevel = level; 
276      > elseif level = 3 then 
277      >     update teacher set tecSalary = 7000 where tecLevel = level; 
278      > elseif level = 4 then
279      >     update teacher set tecSalary = 9000 where tecLevel = level; 
280      > else 
281      >     select * from teacher; 
282      > end if; 
283      > end//
284 
285 > show create procedure proName;
286 > show procedure status;
287 > drop procedure proName;
288 
289 
290 2，case 分支
291 case expression
292 when value1 then
293     commands;
294 [when value2 then
295     commands;]
296 [else
297     commands;]
298 end case;
299 
300 mysql> create procedure tec_pro(in level int) 
301      > begin 
302      > case level 
303      > when 1 then 
304      >     update teacher set tecSalary = 4000 where tecLevel = 1; 
305      > when 2 then  
306      >     update teacher set tecSalary = 4500 where tecLevel = 2; 
307      > when 3 then  
308      >     update teacher set tecSalary = 6000 where tecLevel = 3; 
309      > when 3 then  
310      >     update teacher set tecSalary = 6000 where tecLevel = 3; 
311      > when 4 then 
312      >     update teacher set tecSalary = 8000 where tecLevel = 4; 
313      > else 
314      >     select * from teacher; 
315      > end case; 
316      > end//
317 
318 
319 while 循环
320 [loopName:] while condition do
321     commands;
322 end while [loopName];
323 
324 mysql> create procedure show_pro(in id bigint) 
325      > begin 
326      > declare var int; 
327      > set var = 0; 
328      > while var < 6 do 
329      >     select * from course where courseId = id + var; 
330      >     set var = var + 1; 
331      > end while; 
332      > end//
333 
334 
335 repeat-until 循环
336 [loopName:] repeat
337     commands;
338 until condition
339 end repeat [loopName];
340 
341 mysql> create procedure ins_pro2(in name varchar(32)) 
342      > begin 
343      > declare tim int; 
344      > set tim = 1; 
345      > repeat 
346      > insert usename(Name, Time, Level) values(name, tim, tim); 
347      > set tim = tim + 1; 
348      > until tim > 8 
349      > end repeat; 
350      > end//
351 
352 
353 
354 loop 循环
355 loopName: loop
356     commands;
357 end loop loopName;
358 
359 
360 函数创建：
361 create function(...) returns valueType
362 begin
363     commands;
364     return value;
365 end
366 
367 mysql> create function test(n int) returns text 
368      > begin 
369      > declare i int default 0; 
370      > declare s text default ‘‘; 
371      > myloop: loop 
372      >     set i = i + 1; 
373      >     set s = concat(s, "*"); 
374      > if i >= n then 
375      >     leave myloop; 
376      > end if; 
377      > end loop myloop; 
378      > return s; 
379      > end//
380 
381 mysql> select test(4);
382 mysql> set @tt =  test(3);
383 
384 
385 1，游标定义：declare cursorName cursor for select...
386 2，打开游标：open cursorName
387 3，使用fetch cursorName into var1,var2,...命令去遍历select结果数据表里的数据记录
388 4，关闭游标：close cursorName(游标会在对它们做出声明的 begin-end 语句块执行终了时自动随之结束)
389 备注：若使用fetch命令把select结果数据表的记录都读完了会出发一个错误：no data to fetch。
390 对于该错误可以定义一个错误处理器来捕获。出错处理条件一般使用 not found 即可
391 
392 mysql> create procedure cur_pro2() 
393      > begin 
394      > declare result varchar(256) default ‘‘; 
395      > declare name varchar(32); 
396      > declare done int default 0;
397      > declare cur_book cursor for select courseName from course; 
398      > declare continue handler for not found set done = 1; 
399      > open cur_book; 
400      > repeat 
401      >     fetch cur_book into name; 
402      >     set result = concat(result, name); 
403      > until done 
404      > end repeat; 
405      > select result; 
406      > close cur_book; 
407      > end//

一、基础

1、说明：创建数据库
CREATE DATABASE database-name 
2、说明：删除数据库
drop database dbname
3、说明：备份sql server
— 创建 备份数据的 device
USE master
EXEC sp_addumpdevice ‘disk’, ‘testBack’, ‘c:\mssql7backup\MyNwind_1.dat’
— 开始 备份
BACKUP DATABASE pubs TO testBack
4、说明：创建新表
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..)

根据已有的表创建新表： 
A：create table tab_new like tab_old (使用旧表创建新表)
B：create table tab_new as select col1,col2… from tab_old definition only
5、说明：删除新表
drop table tabname
6、说明：增加一个列
Alter table tabname add column col type
注：列增加后将不能删除。DB2中列加上后数据类型也不能改变，唯一能改变的是增加varchar类型的长度。
7、说明：添加主键： Alter table tabname add primary key(col)
说明：删除主键： Alter table tabname drop primary key(col) 
8、说明：创建索引：create [unique] index idxname on tabname(col….)
删除索引：drop index idxname
注：索引是不可更改的，想更改必须删除重新建。
9、说明：创建视图：create view viewname as select statement 
删除视图：drop view viewname
10、说明：几个简单的基本的sql语句


选择：select * from table1 where 范围
插入：insert into table1(field1,field2) values(value1,value2)
删除：delete from table1 where 范围
更新：update table1 set field1=value1 where 范围
查找：select * from table1 where field1 like ’%value1%’ —like的语法很精妙，查资料!
排序：select * from table1 order by field1,field2 [desc]
总数：select count as totalcount from table1
求和：select sum(field1) as sumvalue from table1
平均：select avg(field1) as avgvalue from table1
最大：select max(field1) as maxvalue from table1
最小：select min(field1) as minvalue from table1
11、说明：几个高级查询运算词
A： UNION 运算符
UNION 运算符通过组合其他两个结果表（例如 TABLE1 和 TABLE2）并消去表中任何重复行而派生出
一个结果表。当 ALL 随 UNION 一起使用时（即 UNION ALL），
不消除重复行。两种情况下，派生表的每一行不是来自 TABLE1 就是来自 TABLE2。
B： EXCEPT 运算符
EXCEPT运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。
当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL)，不消除重复行。
C： INTERSECT 运算符
INTERSECT运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。
当 ALL随 INTERSECT 一起使用时 (INTERSECT ALL)，不消除重复行。
注：使用运算词的几个查询结果行必须是一致的。
12、说明：使用外连接
A、left （outer） join：
左外连接（左连接）：结果集几包括连接表的匹配行，也包括左连接表的所有行。
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c
B：right （outer） join: 
右外连接(右连接)：结果集既包括连接表的匹配连接行，也包括右连接表的所有行。
C：full/cross （outer） join：
全外连接：不仅包括符号连接表的匹配行，还包括两个连接表中的所有记录。
12、分组:Group by:
一张表，一旦分组 完成后，查询后只能得到组相关的信息。
组相关的信息：（统计信息） count,sum,max,min,avg 分组的标准)
在SQLServer中分组时：不能以text,ntext,image类型的字段作为分组依据
在selecte统计函数中的字段，不能和普通的字段放在一起；

13、对数据库进行操作：
分离数据库： sp_detach_db;附加数据库：sp_attach_db 后接表明，附加需要完整的路径名
14.如何修改数据库的名称:
sp_renamedb ‘old_name’, ‘new_name’

二、提升
1、说明：复制表(只复制结构,源表名：a 新表名：b) (Access可用)
法一：select * into b from a where 1<>1（仅用于SQlServer）
法二：select top 0 * into b from a
2、说明：拷贝表(拷贝数据,源表名：a 目标表名：b) (Access可用)
insert into b(a, b, c) select d,e,f from b;

3、说明：跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用)
insert into b(a, b, c) select d,e,f from b in ‘具体数据库’ where 条件
例子：..from b in ‘”&Server.MapPath(“.”)&”\data.mdb” &”‘ where..

4、说明：子查询(表名1：a 表名2：b)
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3)

5、说明：显示文章、提交人和最后回复时间
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b

6、说明：外连接查询(表名1：a 表名2：b)
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c

7、说明：在线视图查询(表名1：a )
select * from (SELECT a,b,c FROM a) T where t.a > 1;

8、说明：between的用法,between限制查询数据范围时包括了边界值,not between不包括
select * from table1 where time between time1 and time2
select a,b,c, from table1 where a not between 数值1 and 数值2

9、说明：in 的使用方法
select * from table1 where a [not] in (‘值1’,’值2’,’值4’,’值6’)

10、说明：两张关联表，删除主表中已经在副表中没有的信息
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 )

11、说明：四表联查问题：
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where …..

12、说明：日程安排提前五分钟提醒
SQL: select * from 日程安排 where datediff(‘minute’,f开始时间,getdate())>5

13、说明：一条sql 语句搞定数据库分页
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段
具体实现：
关于数据库分页：

declare @start int,@end int

@sqlnvarchar(600)

set @sql=’select top’+str(@end-@start+1)+’+from T where rid not in(select top’+str(@str-1)+’Rid from T where Rid>-1)’

exec sp_executesql @sql


注意：在top后不能直接跟一个变量，所以在实际应用中只有这样的进行特殊的处理。Rid为一个标识列，如果top后还有具体的字段，这样做是非常有好处的。因为这样可以避免 top的字段如果是逻辑索引的，查询的结果后实际表中的不一致（逻辑索引中的数据有可能和数据表中的不一致，而查询时如果处在索引则首先查询索引）

14、说明：前10条记录
select top 10 * form table1 where 范围

15、说明：选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.)
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b)

16、说明：包括所有在 TableA中但不在 TableB和TableC中的行并消除所有重复行而派生出一个结果表
(select a from tableA ) except (select a from tableB) except (select a from tableC)

17、说明：随机取出10条数据
select top 10 * from tablename order by newid()

18、说明：随机选择记录
select newid()

19、说明：删除重复记录
1),delete from tablename where id not in (select max(id) from tablename group by col1,col2,…)
2),select distinct * into temp from tablename
delete from tablename
insert into tablename select * from temp
评价： 这种操作牵连大量的数据的移动，这种做法不适合大容量但数据操作
3),例如：在一个外部表中导入数据，由于某些原因第一次只导入了一部分，但很难判断具体位置，这样只有在下一次全部导入，这样也就产生好多重复的字段，怎样删除重复字段

alter table tablename
–添加一个自增列
addcolumn_b int identity(1,1)
delete from tablename where column_b not in(
select max(column_b)from tablename group by column1,column2,…)
alter table tablename drop column column_b

20、说明：列出数据库里所有的表名
select name from sysobjects where type=’U’ // U代表用户

21、说明：列出表里的所有的列名
select name from syscolumns where id=object_id(‘TableName’)

22、说明：列示type、vender、pcs字段，以type字段排列，case可以方便地实现多重选择，类似select 中的case。
select type,sum(case vender when ‘A’ then pcs else 0 end),sum(case vender when ‘C’ then pcs else 0 end),sum(case vender when ‘B’ then pcs else 0 end) FROM tablename group by type
显示结果：
type vender pcs
电脑 A 1
电脑 A 1
光盘 B 2
光盘 A 2
手机 B 3
手机 C 3

23、说明：初始化表table1

TRUNCATE TABLE table1

24、说明：选择从10到15的记录
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc

三、技巧

1、1=1，1=2的使用，在SQL语句组合时用的较多

“where 1=1” 是表示选择全部 “where 1=2”全部不选，
如：
if @strWhere !=”
begin
set @strSQL = ‘select count(*) as Total from [‘ + @tblName + ‘] where ‘ + @strWhere
end
else
begin
set @strSQL = ‘select count(*) as Total from [‘ + @tblName + ‘]‘
end

我们可以直接写成

错误！未找到目录项。
set @strSQL = ‘select count(*) as Total from [‘ + @tblName + ‘] where 1=1 安定 ‘+ @strWhere 2、收缩数据库
–重建索引
DBCC REINDEX
DBCC INDEXDEFRAG
–收缩数据和日志
DBCC SHRINKDB
DBCC SHRINKFILE

3、压缩数据库
dbcc shrinkdatabase(dbname)

4、转移数据库给新用户以已存在用户权限
exec sp_change_users_login ‘update_one’,‘newname’,‘oldname’
go

5、检查备份集
RESTORE VERIFYONLY from disk=’E:\dvbbs.bak’

6、修复数据库
ALTER DATABASE [dvbbs] SET SINGLE_USER
GO
DBCC CHECKDB(‘dvbbs’,repair_allow_data_loss) WITH TABLOCK
GO
ALTER DATABASE [dvbbs] SET MULTI_USER
GO

7、日志清除
SET NOCOUNT ON
DECLARE @LogicalFileName sysname,
@MaxMinutes INT,
@NewSize INT


USE tablename — 要操作的数据库名
SELECT @LogicalFileName = ‘tablename_log’, — 日志文件名
@MaxMinutes = 10, — Limit on time allowed to wrap log.
@NewSize = 1 — 你想设定的日志文件的大小(M)

Setup / initialize
DECLARE @OriginalSize int
SELECT @OriginalSize = size
FROM sysfiles
WHERE name = @LogicalFileName
SELECT ‘Original Size of ‘ + db_name() + ‘ LOG is ‘ +
CONVERT(VARCHAR(30),@OriginalSize) + ‘ 8K pages or ‘ +
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + ‘MB’
FROM sysfiles
WHERE name = @LogicalFileName
CREATE TABLE DummyTrans
(DummyColumn char (8000) not null)


DECLARE @Counter INT,
@StartTime DATETIME,
@TruncLog VARCHAR(255)
SELECT @StartTime = GETDATE(),
@TruncLog = ‘BACKUP LOG ‘ + db_name() + ‘ WITH TRUNCATE_ONLY’

DBCC SHRINKFILE (@LogicalFileName, @NewSize)
EXEC (@TruncLog)
– Wrap the log if necessary.
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) — time has not expired
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName)
AND (@OriginalSize * 8 /1024) > @NewSize
BEGIN — Outer loop.
SELECT @Counter = 0
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000))
BEGIN — update
INSERT DummyTrans VALUES (‘Fill Log’) DELETE DummyTrans
SELECT @Counter = @Counter + 1
END
EXEC (@TruncLog)
END
SELECT ‘Final Size of ‘ + db_name() + ‘ LOG is ‘ +
CONVERT(VARCHAR(30),size) + ‘ 8K pages or ‘ +
CONVERT(VARCHAR(30),(size*8/1024)) + ‘MB’
FROM sysfiles
WHERE name = @LogicalFileName
DROP TABLE DummyTrans
SET NOCOUNT OFF

8、说明：更改某个表
exec sp_changeobjectowner ‘tablename’,‘dbo’

9、存储更改全部表

CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch
@OldOwner as NVARCHAR(128),
@NewOwner as NVARCHAR(128)
AS

DECLARE @Name as NVARCHAR(128)
DECLARE @Owner as NVARCHAR(128)
DECLARE @OwnerName as NVARCHAR(128)

DECLARE curObject CURSOR FOR
select ‘Name’ = name,
‘Owner’ = user_name(uid)
from sysobjects
where user_name(uid)=@OldOwner
order by name

OPEN curObject
FETCH NEXT FROM curObject INTO @Name, @Owner
WHILE(@@FETCH_STATUS=0)
BEGIN
if @Owner=@OldOwner
begin
set @OwnerName = @OldOwner + ‘.’ + rtrim(@Name)
exec sp_changeobjectowner @OwnerName, @NewOwner
end
– select @name,@NewOwner,@OldOwner

FETCH NEXT FROM curObject INTO @Name, @Owner
END

close curObject
deallocate curObject
GO


10、SQL SERVER中直接循环写入数据
declare @i int
set @i=1
while @i<30
begin
insert into test (userid) values(@i)
set @i=@i+1
end
案例：
有如下表，要求就裱中所有沒有及格的成績，在每次增長0.1的基礎上，使他們剛好及格:

Namescore

Zhangshan80

Lishi 59

Wangwu 50

Songquan69

while((select min(score) from tb_table)<60)

begin

update tb_table set score =score*1.01

where score<60

if(select min(score) from tb_table)>60

break

else

continue

end

数据开发-经典

1.按姓氏笔画排序:
Select * From TableName Order By CustomerName Collate Chinese_PRC_Stroke_ci_as //从少到多

2.数据库加密:
select encrypt(‘原始密码‘)
select pwdencrypt(‘原始密码‘)
select pwdcompare(‘原始密码‘,’加密后密码‘) = 1–相同；否则不相同 encrypt(‘原始密码‘)
select pwdencrypt(‘原始密码‘)
select pwdcompare(‘原始密码‘,’加密后密码‘) = 1–相同；否则不相同

3.取回表中字段:
declare @list varchar(1000),
@sql nvarchar(1000)
select @list=@list+‘,’+b.name from sysobjects a,syscolumns b where a.id=b.id and a.name=‘表A’
set @sql=‘select ‘+right(@list,len(@list)-1)+‘ from 表A‘
exec (@sql)

4.查看硬盘分区:
EXEC master..xp_fixeddrives

5.比较A,B表是否相等:
if (select checksum_agg(binary_checksum(*)) from A)
=
(select checksum_agg(binary_checksum(*)) from B)
print ‘相等‘
else
print ‘不相等‘

6.杀掉所有的事件探察器进程:
DECLARE hcforeach CURSOR GLOBAL FOR SELECT ‘kill ‘+RTRIM(spid) FROM master.dbo.sysprocesses
WHERE program_name IN(‘SQL profiler’,N’SQL 事件探查器‘)
EXEC sp_msforeach_worker ‘?‘

7.记录搜索:
开头到N条记录
Select Top N * From 表
——————————-
N到M条记录(要有主索引ID)
Select Top M-N * From 表 Where ID in (Select Top M ID From 表) Order by ID Desc
———————————-
N到结尾记录
Select Top N * From 表 Order by ID Desc
案例
例如1：一张表有一万多条记录，表的第一个字段 RecID 是自增长字段， 写一个SQL语句， 找出表的第31到第40个记录。

select top 10 recid from A where recid notin(select top 30 recid from A)

分析：如果这样写会产生某些问题，如果recid在表中存在逻辑索引。

select top 10 recid from A where……是从索引中查找，而后面的select top 30 recid from A则在数据表中查找，这样由于索引中的顺序有可能和数据表中的不一致，这样就导致查询到的不是本来的欲得到的数据。

解决方案

1，用order by select top 30 recid from A order by ricid 如果该字段不是自增长，就会出现问题

2，在那个子查询中也加条件：select top 30 recid from A where recid>-1

例2：查询表中的最后以条记录，并不知道这个表共有多少数据,以及表结构。
set @s = ‘select top 1 * from Twhere pid not in (select top ‘ + str(@count-1) + ‘ pidfrom T)’

print @sexecsp_executesql@s

9：获取当前数据库中的所有用户表
select Name from sysobjects where xtype=’u’ and status>=0

10：获取某一个表的所有字段
select name from syscolumns where id=object_id(‘表名‘)

select name from syscolumns where id in (select id from sysobjects where type = ‘u’ and name = ‘表名‘)

两种方式的效果相同

11：查看与某一个表相关的视图、存储过程、函数
select a.* from sysobjects a, syscomments b where a.id = b.id and b.text like ‘%表名%’

12：查看当前数据库中所有存储过程
select name as 存储过程名称 from sysobjects where xtype=’P’

13：查询用户创建的所有数据库
select * from master..sysdatabases D where sid not in(select sid from master..syslogins where name=’sa’)
或者
select dbid, name AS DB_NAME from master..sysdatabases where sid <> 0×01

14：查询某一个表的字段和数据类型
select column_name,data_type from information_schema.columns
where table_name = ‘表名‘

15：不同服务器数据库之间的数据操作

–创建链接服务器

exec sp_addlinkedserver’ITSV ‘, ‘ ‘, ‘SQLOLEDB ‘, ‘远程服务器名或ip地址 ‘

exec sp_addlinkedsrvlogin’ITSV ‘, ‘false ‘,null, ‘用户名 ‘, ‘密码 ‘

–查询示例

select * from ITSV.数据库名.dbo.表名

–导入示例

select * into 表 from ITSV.数据库名.dbo.表名

–以后不再使用时删除链接服务器

exec sp_dropserver’ITSV ‘, ‘droplogins ‘

–连接远程/局域网数据(openrowset/openquery/opendatasource)
–1、openrowset

–查询示例

select * from openrowset( ‘SQLOLEDB ‘, ‘sql服务器名 ‘; ‘用户名 ‘; ‘密码 ‘,数据库名.dbo.表名)

–生成本地表

select * into 表 from openrowset( ‘SQLOLEDB ‘, ‘sql服务器名 ‘; ‘用户名 ‘; ‘密码 ‘,数据库名.dbo.表名)

–把本地表导入远程表
insert openrowset( ‘SQLOLEDB ‘, ‘sql服务器名 ‘; ‘用户名 ‘; ‘密码 ‘,数据库名.dbo.表名)

select *from 本地表

–更新本地表

update b

set b.列A=a.列A

from openrowset( ‘SQLOLEDB ‘, ‘sql服务器名 ‘; ‘用户名 ‘; ‘密码 ‘,数据库名.dbo.表名)as a inner join 本地表 b

on a.column1=b.column1

–openquery用法需要创建一个连接

--首先创建一个连接创建链接服务器

exec sp_addlinkedserver’ITSV ‘, ‘ ‘, ‘SQLOLEDB ‘, ‘远程服务器名或ip地址 ‘

–查询

select *

FROM openquery(ITSV,’SELECT *FROM 数据库.dbo.表名 ‘)

–把本地表导入远程表

insert openquery(ITSV,’SELECT *FROM 数据库.dbo.表名 ‘)

select * from 本地表

–更新本地表

update b

set b.列B=a.列B

FROM openquery(ITSV,’SELECT * FROM 数据库.dbo.表名 ‘) as a

inner join 本地表 b on a.列A=b.列A

–3、opendatasource/openrowset
SELECT*

FROMopendatasource( ‘SQLOLEDB ‘,’Data Source=ip/ServerName;User ID=登陆名;Password=密码 ‘ ).test.dbo.roy_ta

–把本地表导入远程表

insert opendatasource( ‘SQLOLEDB ‘,’Data Source=ip/ServerName;User ID=登陆名;Password=密码 ‘).数据库.dbo.表名

select * from 本地表


SQL Server基本函数

SQL Server基本函数

1.字符串函数 长度与分析用

1,datalength(Char_expr) 返回字符串包含字符数,但不包含后面的空格
2,substring(expression,start,length) 取子串，字符串的下标是从“1”，start为起始位置，length为字符串长度，实际应用中以len(expression)取得其长度
3,right(char_expr,int_expr) 返回字符串右边第int_expr个字符，还用left于之相反
4,isnull( check_expression , replacement_value )如果check_expression為空，則返回replacement_value的值，不為空，就返回check_expression字符操作类

5,Sp_addtype自定義數據類型
例如：EXEC sp_addtype birthday, datetime, ‘NULL‘




? 2015 内存溢出