數據庫操做----找了MySQL和SQL Sever兩個的基礎語句

這是MySQL的基本操做：
  1 登入數據庫：mysql -uroot -p+密碼 (SQL Sever登入： osql  -U 用戶名  -P 密碼)
  2 顯示已存在的數據庫：show databases;
  3 使用某個數據庫：use+數據庫名;
  4 顯示某個數據庫下已存在的關係表：show tables;
  5 
  6 查看某個關係表全部數據：select * from tableName;
  7 查看某個關係表部分字段數據：select 字段1，字段2，...，字段n from tableName;
  8 查看n條記錄：select ... from ... limit n;
  9 查看第i條到第j條之間的記錄：select ... from ... limit i,j;
 10 
 11 使用order by 來對記錄進行排序，默認從小到大
 12 >select stuName, stuScore from student order by stuScore desc;  //（從大到小）
 13 >select stuName, stuScore from student order by stuScore asc;   //（從小到大）
 14 
 15 去重: distinct
 16 >select distinct stuCourse from student;
 17 > select count(distinct stuCourse) from student;
 18 
 19 
 20 聚合函數(經常使用於GROUP BY從句的SELECT查詢中)
 21 AVG(col)返回指定列的平均值
 22 COUNT(col)返回指定列中非NULL值的個數
 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)返回指定列的全部值之和
 26 GROUP_CONCAT(col) 返回由屬於一組的列值鏈接組合而成的結果
 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 條件限制：where : =, !=, >, >=, <, <=, and, not, or
 36          , between...and..., not between...and...
 37          , is null, is not null, like(%, _), not like(%, _)
 38          , in(項1, 項2, …), not in(項1, 項2, …)
 39          , exists, not exists
 40          , any, some, all
 41 
 42 %: 匹配任意個字符
 43 _：匹配單個字符
 44 
 45 建立數據庫：create database 數據庫名;
 46 建立關係表：create table tableName(字段1 類型 限制，字段2 類型 限制，...,字段n 類型 限制);
 47 顯示關係表的格式：show create table tableName;
 48 更新數據：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 插入數據：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 生成一個關係表的備份：create table baktableName (select * from tableName);
 53 使用備份的數據對新表插入數據
 54 > insert book select * from bookBak;
 55 
 56 生成一個數據庫的備份：mysqldump -uUserName -p dbname > bakefile;
 57 使用數據庫的備份恢復數據庫：mysql -uUserName -p dbname < bakefile;
 58 
 59 使用交互方式恢復數據庫：
 60 > create database dbName; (若是不存在這個數據庫)
 61 > use dbName;
 62 > source bakeFile;
 63 
 64 刪除一個數據庫：drop database dbname;
 65 刪除關係表中全部數據：delete from tableName;    
 66 刪除關係表中符合條件的數據：delete from tableName where...;
 67 
 68 給關係表增長一個字段：alter table tableName add 字段名 說明(default 'H');
 69 給關係表刪除一個字段：alter table tableName drop 字段名;
 70 給關係表修改一個字段：alter table tableName modify 字段名 說明;
 71 給關係表修改一個字段：alter table tableName change 舊字段名 新字段名 說明(類型...);
 72 
 73 設置字段值惟一，即該字段的值不容許有重複的: unique
 74 > create table tmp(id int unique not null, name varchar(32));
 75 
 76 主鍵：惟一標識一條記錄，主鍵能夠是單個字段，也能夠是多個字段合成的
 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 多表查詢
 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 外鍵
 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 學生表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 教師表 teacher(tecId,tecName) 
106 mysql> create table teacher(tecId varchar(32) primary key not null,
107     -> tecName varchar(32) not null);
108 
109 課程表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 成績表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 級聯操做：
126     foreign key(column) references tableName(column) 
127     [[on delete | on update] [cascade | no action | set null | restrict]];
128 
129 
130 查詢每一個學生每門課的成績
131 > select stuName, courseName, score from student, course, score where student.stuId = score.stuId 
132   and course.courseId = score.courseId;
133 
134 查詢每一個學生的總成績
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 對每一個學生的總成績排序
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 查詢每一個學生的平均成績
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 查詢平均成績>80的學生
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字句可讓咱們篩選成組後的各類數據，where字句在聚合前先篩選記錄，也就是說做用在group by和having字句前。而 having子句在聚合後對組記錄進行篩選。
149 
150 查詢「3004」課程比「3002」課程成績高的全部學生的學號
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 查詢全部同窗的學號、姓名、課數、總成績
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 查詢和likui性別相同的學生信息
165 > select stuId, stuName from student where stuSex = (select stuSex from student where stuName = "likui") 
166   and stuName != "likui";
167 
168 查詢沒學過「mozi」老師課的同窗的學號、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 查詢每一個老師所教課程平均分從高到低顯示
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 刪除學習「laozi」老師課的score表記錄
185 > delete from score where courseId in (select courseId from course 
186   where tecId = (select tecId from teacher where tecName = "laozi"));
187 
188 查詢兩門及以上不及格課程的同窗的學號及其平均成績
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 查詢各科成績最高和最低的分：以以下形式顯示：課程ID，最高分，最低分
194 > select courseId, max(score), min(score) from score group by courseId;    
195 
196 查詢學過「3001」而且也學過編號「3003」課程的同窗的學號、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 查詢「3001」課程的分數比「3001」課程平均分低的學生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 查詢「3001」課程的分數比「3001」課程平均分低的學生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 查詢「3001」課程的分數比「3001」課程平均分低的學生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: 是視圖，是一張虛表，表中沒有任何數據
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 存儲過程：
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 循環
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 循環
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 循環
355 loopName: loop
356     commands;
357 end loop loopName;
358 
359 
360 函數建立：
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，遊標定義：declare cursorName cursor for select...
386 2，打開遊標：open cursorName
387 3，使用fetch cursorName into var1,var2,...命令去遍歷select結果數據表裏的數據記錄
388 4，關閉遊標：close cursorName(遊標會在對它們作出聲明的 begin-end 語句塊執行終了時自動隨之結束)
389 備註：若使用fetch命令把select結果數據表的記錄都讀完了會出發一個錯誤：no data to fetch。
390 對於該錯誤能夠定義一個錯誤處理器來捕獲。出錯處理條件通常使用 not found 便可
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//

下面是SQL Sever的語法，其實基本上差很少，這兩天我所用到，大概也就一個遞增、一個級聯不一樣

1、基礎

1、說明：建立數據庫
CREATE DATABASE database-name 
2、說明：刪除數據庫
drop database dbname
3、說明：備份sql server
— 建立 備份數據的 device
USE master
EXEC sp_addumpdevice ‘disk’, ‘testBack’, ‘c:\mssql7backup\MyNwind_1.dat’
— 開始 備份
BACKUP DATABASE pubs TO testBack
4、說明：建立新表
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..)

根據已有的表建立新表： 
A：create table tab_new like tab_old (使用舊錶建立新表)
B：create table tab_new as select col1,col2… from tab_old definition only
5、說明：刪除新表
drop table tabname
6、說明：增長一個列
Alter table tabname add column col type
注：列增長後將不能刪除。DB2中列加上後數據類型也不能改變，惟一能改變的是增長varchar類型的長度。
7、說明：添加主鍵： Alter table tabname add primary key(col)
說明：刪除主鍵： Alter table tabname drop primary key(col) 
8、說明：建立索引：create [unique] index idxname on tabname(col….)
刪除索引：drop index idxname
注：索引是不可更改的，想更改必須刪除從新建。
9、說明：建立視圖：create view viewname as select statement 
刪除視圖：drop view viewname
10、說明：幾個簡單的基本的sql語句


選擇：select * from table1 where 範圍
插入：insert into table1(field1,field2) values(value1,value2)
刪除：delete from table1 where 範圍
更新：update table1 set field1=value1 where 範圍
查找：select * from table1 where field1 like ’%value1%’ —like的語法很精妙，查資料!
排序：select * from table1 order by field1,field2 [desc]
總數：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、說明：幾個高級查詢運算詞
A： UNION 運算符
UNION 運算符經過組合其餘兩個結果表（例如 TABLE1 和 TABLE2）並消去表中任何重複行而派生出
一個結果表。當 ALL 隨 UNION 一塊兒使用時（即 UNION ALL），
不消除重複行。兩種狀況下，派生表的每一行不是來自 TABLE1 就是來自 TABLE2。
B： EXCEPT 運算符
EXCEPT運算符經過包括全部在 TABLE1 中但不在 TABLE2 中的行並消除全部重複行而派生出一個結果表。
當 ALL 隨 EXCEPT 一塊兒使用時 (EXCEPT ALL)，不消除重複行。
C： INTERSECT 運算符
INTERSECT運算符經過只包括 TABLE1 和 TABLE2 中都有的行並消除全部重複行而派生出一個結果表。
當 ALL隨 INTERSECT 一塊兒使用時 (INTERSECT ALL)，不消除重複行。
注：使用運算詞的幾個查詢結果行必須是一致的。
12、說明：使用外鏈接
A、left （outer） join：
左外鏈接（左鏈接）：結果集幾包括鏈接表的匹配行，也包括左鏈接表的全部行。
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: 
右外鏈接(右鏈接)：結果集既包括鏈接表的匹配鏈接行，也包括右鏈接表的全部行。
C：full/cross （outer） join：
全外鏈接：不只包括符號鏈接表的匹配行，還包括兩個鏈接表中的全部記錄。
12、分組:Group by:
一張表，一旦分組 完成後，查詢後只能獲得組相關的信息。
組相關的信息：（統計信息） count,sum,max,min,avg 分組的標準)
在SQLServer中分組時：不能以text,ntext,image類型的字段做爲分組依據
在selecte統計函數中的字段，不能和普通的字段放在一塊兒；

13、對數據庫進行操做：
分離數據庫： sp_detach_db;附加數據庫：sp_attach_db 後接代表，附加須要完整的路徑名
14.如何修改數據庫的名稱:
sp_renamedb ‘old_name’, ‘new_name’

2、提高
1、說明：複製表(只複製結構,源表名：a 新表名：b) (Access可用)
法一：select * into b from a where 1<>1（僅用於SQlServer）
法二：select top 0 * into b from a
2、說明：拷貝表(拷貝數據,源表名：a 目標表名：b) (Access可用)
insert into b(a, b, c) select d,e,f from b;

3、說明：跨數據庫之間表的拷貝(具體數據使用絕對路徑) (Access可用)
insert into b(a, b, c) select d,e,f from b in ‘具體數據庫’ where 條件
例子：..from b in ‘」&Server.MapPath(「.」)&」\data.mdb」 &」‘ where..

4、說明：子查詢(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、說明：顯示文章、提交人和最後回覆時間
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b

6、說明：外鏈接查詢(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、說明：在線視圖查詢(表名1：a )
select * from (SELECT a,b,c FROM a) T where t.a > 1;

8、說明：between的用法,between限制查詢數據範圍時包括了邊界值,not between不包括
select * from table1 where time between time1 and time2
select a,b,c, from table1 where a not between 數值1 and 數值2

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

10、說明：兩張關聯表，刪除主表中已經在副表中沒有的信息
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 )

11、說明：四表聯查問題：
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、說明：日程安排提早五分鐘提醒
SQL: select * from 日程安排 where datediff(‘minute’,f開始時間,getdate())>5

13、說明：一條sql 語句搞定數據庫分頁
select top 10 b.* from (select top 20 主鍵字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主鍵字段 = a.主鍵字段 order by a.排序字段
具體實現：
關於數據庫分頁：

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後不能直接跟一個變量，因此在實際應用中只有這樣的進行特殊的處理。Rid爲一個標識列，若是top後還有具體的字段，這樣作是很是有好處的。由於這樣能夠避免 top的字段若是是邏輯索引的，查詢的結果後實際表中的不一致（邏輯索引中的數據有可能和數據表中的不一致，而查詢時若是處在索引則首先查詢索引）

14、說明：前10條記錄
select top 10 * form table1 where 範圍

15、說明：選擇在每一組b值相同的數據中對應的a最大的記錄的全部信息(相似這樣的用法能夠用於論壇每個月排行榜,每個月熱銷產品分析,按科目成績排名,等等.)
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b)

16、說明：包括全部在 TableA中但不在 TableB和TableC中的行並消除全部重複行而派生出一個結果表
(select a from tableA ) except (select a from tableB) except (select a from tableC)

17、說明：隨機取出10條數據
select top 10 * from tablename order by newid()

18、說明：隨機選擇記錄
select newid()

19、說明：刪除重複記錄
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
評價： 這種操做牽連大量的數據的移動，這種作法不適合大容量但數據操做
3),例如：在一個外部表中導入數據，因爲某些緣由第一次只導入了一部分，但很難判斷具體位置，這樣只有在下一次所有導入，這樣也就產生好多重複的字段，怎樣刪除重複字段

alter table tablename
–添加一個自增列
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、說明：列出數據庫裏全部的表名
select name from sysobjects where type=’U’ // U表明用戶

21、說明：列出表裏的全部的列名
select name from syscolumns where id=object_id(‘TableName’)

22、說明：列示type、vender、pcs字段，以type字段排列，case能夠方便地實現多重選擇，相似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
顯示結果：
type vender pcs
電腦 A 1
電腦 A 1
光盤 B 2
光盤 A 2
手機 B 3
手機 C 3

23、說明：初始化表table1

TRUNCATE TABLE table1

24、說明：選擇從10到15的記錄
select top 5 * from (select top 15 * from table order by id asc) table_別名 order by id desc

3、技巧

1、1=1，1=2的使用，在SQL語句組合時用的較多

「where 1=1」 是表示選擇所有 「where 1=2」所有不選，
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

咱們能夠直接寫成

錯誤！未找到目錄項。
set @strSQL = ‘select count(*) as Total from [' + @tblName + '] where 1=1 安定 ‘+ @strWhere 2、收縮數據庫
–重建索引
DBCC REINDEX
DBCC INDEXDEFRAG
–收縮數據和日誌
DBCC SHRINKDB
DBCC SHRINKFILE

3、壓縮數據庫
dbcc shrinkdatabase(dbname)

4、轉移數據庫給新用戶以已存在用戶權限
exec sp_change_users_login ‘update_one’,'newname’,'oldname’
go

5、檢查備份集
RESTORE VERIFYONLY from disk=’E:\dvbbs.bak’

6、修復數據庫
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、日誌清除
SET NOCOUNT ON
DECLARE @LogicalFileName sysname,
@MaxMinutes INT,
@NewSize INT


USE tablename — 要操做的數據庫名
SELECT @LogicalFileName = ‘tablename_log’, — 日誌文件名
@MaxMinutes = 10, — Limit on time allowed to wrap log.
@NewSize = 1 — 你想設定的日誌文件的大小(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、說明：更改某個表
exec sp_changeobjectowner ‘tablename’,'dbo’

9、存儲更改所有表

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中直接循環寫入數據
declare @i int
set @i=1
while @i<30
begin
insert into test (userid) values(@i)
set @i=@i+1
end
案例：
有以下表，要求就裱中全部沒有及格的成績，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

數據開發-經典

1.按姓氏筆畫排序:
Select * From TableName Order By CustomerName Collate Chinese_PRC_Stroke_ci_as //從少到多

2.數據庫加密:
select encrypt(‘原始密碼‘)
select pwdencrypt(‘原始密碼‘)
select pwdcompare(‘原始密碼‘,’加密後密碼‘) = 1–相同；不然不相同 encrypt(‘原始密碼‘)
select pwdencrypt(‘原始密碼‘)
select pwdcompare(‘原始密碼‘,’加密後密碼‘) = 1–相同；不然不相同

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.查看硬盤分區:
EXEC master..xp_fixeddrives

5.比較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.殺掉全部的事件探察器進程:
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.記錄搜索:
開頭到N條記錄
Select Top N * From 表
——————————-
N到M條記錄(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到結尾記錄
Select Top N * From 表 Order by ID Desc
案例
例如1：一張表有一萬多條記錄，表的第一個字段 RecID 是自增加字段， 寫一個SQL語句， 找出表的第31到第40個記錄。

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

分析：若是這樣寫會產生某些問題，若是recid在表中存在邏輯索引。

select top 10 recid from A where……是從索引中查找，然後面的select top 30 recid from A則在數據表中查找，這樣因爲索引中的順序有可能和數據表中的不一致，這樣就致使查詢到的不是原本的欲獲得的數據。

解決方案

1，用order by select top 30 recid from A order by ricid 若是該字段不是自增加，就會出現問題

2，在那個子查詢中也加條件：select top 30 recid from A where recid>-1

例2：查詢表中的最後以條記錄，並不知道這個表共有多少數據,以及表結構。
set @s = ‘select top 1 * from Twhere pid not in (select top ‘ + str(@count-1) + ‘ pidfrom T)’

print @sexecsp_executesql@s

9：獲取當前數據庫中的全部用戶表
select Name from sysobjects where xtype=’u’ and status>=0

10：獲取某一個表的全部字段
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‘)

兩種方式的效果相同

11：查看與某一個表相關的視圖、存儲過程、函數
select a.* from sysobjects a, syscomments b where a.id = b.id and b.text like ‘%表名%’

12：查看當前數據庫中全部存儲過程
select name as 存儲過程名稱 from sysobjects where xtype=’P’

13：查詢用戶建立的全部數據庫
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：查詢某一個表的字段和數據類型
select column_name,data_type from information_schema.columns
where table_name = ‘表名‘

15：不一樣服務器數據庫之間的數據操做

–建立連接服務器

exec sp_addlinkedserver’ITSV ‘, ‘ ‘, ‘SQLOLEDB ‘, ‘遠程服務器名或ip地址 ‘

exec sp_addlinkedsrvlogin’ITSV ‘, ‘false ‘,null, ‘用戶名 ‘, ‘密碼 ‘

–查詢示例

select * from ITSV.數據庫名.dbo.表名

–導入示例

select * into 表 from ITSV.數據庫名.dbo.表名

–之後再也不使用時刪除連接服務器

exec sp_dropserver’ITSV ‘, ‘droplogins ‘

–鏈接遠程/局域網數據(openrowset/openquery/opendatasource)
–1、openrowset

–查詢示例

select * from openrowset( ‘SQLOLEDB ‘, ‘sql服務器名 ‘; ‘用戶名 ‘; ‘密碼 ‘,數據庫名.dbo.表名)

–生成本地表

select * into 表 from openrowset( ‘SQLOLEDB ‘, ‘sql服務器名 ‘; ‘用戶名 ‘; ‘密碼 ‘,數據庫名.dbo.表名)

–把本地表導入遠程表
insert openrowset( ‘SQLOLEDB ‘, ‘sql服務器名 ‘; ‘用戶名 ‘; ‘密碼 ‘,數據庫名.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服務器名 ‘; ‘用戶名 ‘; ‘密碼 ‘,數據庫名.dbo.表名)as a inner join 本地表 b

on a.column1=b.column1

–openquery用法須要建立一個鏈接

--首先建立一個鏈接建立連接服務器

exec sp_addlinkedserver’ITSV ‘, ‘ ‘, ‘SQLOLEDB ‘, ‘遠程服務器名或ip地址 ‘

–查詢

select *

FROM openquery(ITSV,’SELECT *FROM 數據庫.dbo.表名 ‘)

–把本地表導入遠程表

insert openquery(ITSV,’SELECT *FROM 數據庫.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 數據庫.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=登錄名;Password=密碼 ‘ ).test.dbo.roy_ta

–把本地表導入遠程表

insert opendatasource( ‘SQLOLEDB ‘,’Data Source=ip/ServerName;User ID=登錄名;Password=密碼 ‘).數據庫.dbo.表名

select * from 本地表


SQL Server基本函數

SQL Server基本函數

1.字符串函數 長度與分析用

1,datalength(Char_expr) 返回字符串包含字符數,但不包含後面的空格
2,substring(expression,start,length) 取子串，字符串的下標是從「1」，start爲起始位置，length爲字符串長度，實際應用中以len(expression)取得其長度
3,right(char_expr,int_expr) 返回字符串右邊第int_expr個字符，還用left於之相反
4,isnull( check_expression , replacement_value )若是check_expression為空，則返回replacement_value的值，不為空，就返回check_expression字符操做類

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




? 2015 內存溢出

其實、這些語句，若是須要想不起來，就看一下，很方便的。