精妙SQL語(yǔ)句整理

1、一、基礎(chǔ) 1、說(shuō)明：創(chuàng)建數(shù)據(jù)庫(kù) CREATE DATABASE database-name 2、說(shuō)明：刪除數(shù)據(jù)庫(kù) drop database dbname 3、說(shuō)明：備份sql server - 創(chuàng)建 備份數(shù)據(jù)的 device USE master EXEC sp_addumpdevice 'disk', 'testBack', 'c:mssql7backupMyNwind_1.dat' - 開(kāi)始 備份 BACKUP DATABASE pubs TO testBack 4、說(shuō)明：創(chuàng)建新表 create table tabname(col1 typ

2、e1 not null primary key,col2 type2 not null,.) 根據(jù)已有的表創(chuàng)建新表： A：create table tab_new like tab_old (使用舊表創(chuàng)建新表) B：create table tab_new as select col1,col2 from tab_old definition only 5、說(shuō)明：刪除新表 drop table tabname 6、說(shuō)明：增加一個(gè)列 Alter table tabname add column col type 注：列增加后將不能刪除。DB2中列加上后數(shù)據(jù)類型也不能改變，唯一能改變的是增加var

3、char類型的長(zhǎng)度。 7、說(shuō)明：添加主鍵： Alter table tabname add primary key(col) 說(shuō)明：刪除主鍵： Alter table tabname drop primary key(col) 8、說(shuō)明：創(chuàng)建索引：create unique index idxname on tabname(col.) 刪除索引：drop index idxname 注：索引是不可更改的，想更改必須刪除重新建。 9、說(shuō)明：創(chuàng)建視圖：create view viewname as select statement 刪除視圖：drop view viewname 10、說(shuō)明：幾個(gè)簡(jiǎn)

4、單的基本的sql語(yǔ)句 選擇：select * from table1 where 范圍 插入：insert into table1(field1,field2) values(value1,value2) 刪除：delete from table1 where 范圍 更新：update table1 set field1=value1 where 范圍 查找：select * from table1 where field1 like %value1% -like的語(yǔ)法很精妙，查資料! 排序：select * from table1 order by field1,field2 desc 總數(shù)

5、：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?。簊elect min(field1) as minvalue from table1 11、說(shuō)明：幾個(gè)高級(jí)查詢運(yùn)算詞 A： UNION 運(yùn)算符 UNION 運(yùn)算符通過(guò)組合其他兩個(gè)結(jié)果表（例如 TABLE1 和 TABLE2）并消去表中任何

6、重復(fù)行而派生出一個(gè)結(jié)果表。當(dāng) ALL 隨 UNION 一起使用時(shí)（即 UNION ALL），不消除重復(fù)行。兩種情況下，派生表的每一行不是來(lái)自 TABLE1 就是來(lái)自 TABLE2。 B： EXCEPT 運(yùn)算符 EXCEPT 運(yùn)算符通過(guò)包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重復(fù)行而派生出一個(gè)結(jié)果表。當(dāng) ALL 隨 EXCEPT 一起使用時(shí) (EXCEPT ALL)，不消除重復(fù)行。 C： INTERSECT 運(yùn)算符 INTERSECT 運(yùn)算符通過(guò)只包括 TABLE1 和 TABLE2 中都有的行并消除所有重復(fù)行而派生出一個(gè)結(jié)果表。當(dāng) ALL 隨 INTERSECT 一起

7、使用時(shí) (INTERSECT ALL)，不消除重復(fù)行。 注：使用運(yùn)算詞的幾個(gè)查詢結(jié)果行必須是一致的。 12、說(shuō)明：使用外連接 A、left outer join： 左外連接（左連接）：結(jié)果集幾包括連接表的匹配行，也包括左連接表的所有行。 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: 右外連接(右連接)：結(jié)果集既包括連接表的匹配連接行，也包括右連接表的所有行。 C：full outer join： 全外連接：不僅包括符號(hào)連接表的匹配行，還包括兩個(gè)連接

8、表中的所有記錄。 二、提升 1、說(shuō)明：復(fù)制表(只復(fù)制結(jié)構(gòu),源表名：a 新表名：b) (Access可用) 法一：select * into b from a where 1<>1 法二：select top 0 * into b from a 2、說(shuō)明：拷貝表(拷貝數(shù)據(jù),源表名：a 目標(biāo)表名：b) (Access可用) insert into b(a, b, c) select d,e,f from b; 3、說(shuō)明：跨數(shù)據(jù)庫(kù)之間表的拷貝(具體數(shù)據(jù)使用絕對(duì)路徑) (Access可用) insert into b(a, b, c) select d,e,f from b in '

9、;具體數(shù)據(jù)庫(kù) where 條件 例子：.from b in '"&Server.MapPath(".")&"data.mdb" &"' where. 4、說(shuō)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(shuō)明：顯示文章、提交人和最后回復(fù)時(shí)間 select a.title,a.username,b.adddate fro

10、m table a,(select max(adddate) adddate from table where table.title=a.title) b 6、說(shuō)明：外連接查詢(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(shuō)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(shuō)明：between的用法,between限制查詢數(shù)據(jù)范圍時(shí)包括了邊界值,not betwee

11、n不包括 select * from table1 where time between time1 and time2 select a,b,c, from table1 where a not between 數(shù)值1 and 數(shù)值2 9、說(shuō)明：in 的使用方法 select * from table1 where a not in ('值1,值2,值4,值6) 10、說(shuō)明：兩張關(guān)聯(lián)表，刪除主表中已經(jīng)在副表中沒(méi)有的信息 delete from table1 where not exists ( select * from table2 where table1.field1=tabl

12、e2.field1 ) 11、說(shuō)明：四表聯(lián)查問(wèn)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(shuō)明：日程安排提前五分鐘提醒 SQL: select * from 日程安排 where datediff('minute',f開(kāi)始時(shí)間,getdate()>5 13、說(shuō)明：一條sql 語(yǔ)句搞定數(shù)據(jù)庫(kù)分頁(yè) select top 10 b.* from (select top 20 主鍵字段,排序字段 fr

13、om 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 14、說(shuō)明：前10條記錄 select top 10 * form table1 where 范圍 15、說(shuō)明：選擇在每一組b值相同的數(shù)據(jù)中對(duì)應(yīng)的a最大的記錄的所有信息(類似這樣的用法可以用于論壇每月排行榜,每月熱銷產(chǎn)品分析,按科目成績(jī)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(shuō)明：包括所有在 Ta

14、bleA 中但不在 TableB和TableC 中的行并消除所有重復(fù)行而派生出一個(gè)結(jié)果表 (select a from tableA ) except (select a from tableB) except (select a from tableC) 17、說(shuō)明：隨機(jī)取出10條數(shù)據(jù) select top 10 * from tablename order by newid() 18、說(shuō)明：隨機(jī)選擇記錄 select newid() 19、說(shuō)明：刪除重復(fù)記錄 Delete from tablename where id not in (select max(id) from tablena

15、me group by col1,col2,.) 20、說(shuō)明：列出數(shù)據(jù)庫(kù)里所有的表名 select name from sysobjects where type='U' 21、說(shuō)明：列出表里的所有的 select name from syscolumns where id=object_id('TableName') 22、說(shuō)明：列示type、vender、pcs字段，以type字段排列，case可以方便地實(shí)現(xiàn)多重選擇，類似select 中的case。 select type,sum(case vender when 'A' then pcs

16、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(jié)果： type vender pcs 電腦 A 1 電腦 A 1 光盤(pán) B 2 光盤(pán) A 2 手機(jī) B 3 手機(jī) C 3 23、說(shuō)明：初始化表table1 TRUNCATE TABLE table1 24、說(shuō)明：選擇從10到15的記錄 select top 5 * from (select to

17、p 15 * from table order by id asc) table_別名 order by id desc 三、技巧 1、1=1，1=2的使用，在SQL語(yǔ)句組合時(shí)用的較多 “where 1=1” 是表示選擇全部 “where 1=2”全部不選， 如： if strWhere !='' begin set strSQL = 'select count(*) as Total from ' + tblName + ' where ' + strWhere end else begin set strSQL = 'select c

18、ount(*) as Total from ' + tblName + '' end 我們可以直接寫(xiě)成 set strSQL = 'select count(*) as Total from ' + tblName + ' where 1=1 安定 '+ strWhere 2、收縮數(shù)據(jù)庫(kù) -重建索引 DBCC REINDEX DBCC INDEXDEFRAG -收縮數(shù)據(jù)和日志 DBCC SHRINKDB DBCC SHRINKFILE 3、壓縮數(shù)據(jù)庫(kù) dbcc shrinkdatabase(dbname) 4、轉(zhuǎn)移數(shù)據(jù)庫(kù)給新用戶以已存在用

19、戶權(quán)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(fù)數(shù)據(jù)庫(kù) ALTER DATABASE dvbbs SET SINGLE_USER GO DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK GO ALTER DATABASE dvbbs SET MULTI_US

20、ER GO 7、日志清除 SET NOCOUNT ON DECLARE LogicalFileName sysname, MaxMinutes INT, NewSize INT USE tablename - 要操作的數(shù)據(jù)庫(kù)名 SELECT LogicalFileName = 'tablename_log', - 日志文件名 MaxMinutes = 10, - Limit on time allowed to wrap log. NewSize = 1 - 你想設(shè)定的日志文件的大小(M) - Setup / initialize DECLARE OriginalSize in

21、t 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 = LogicalFileN

22、ame 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 t

23、he 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

24、 (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

25、*8/1024) + 'MB' FROM sysfiles WHERE name = LogicalFileName DROP TABLE DummyTrans SET NOCOUNT OFF 8、說(shuō)明：更改某個(gè)表 exec sp_changeobjectowner 'tablename','dbo' 9、存儲(chǔ)更改全部表 CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch OldOwner as NVARCHAR(128), NewOwner as NVARCHAR(128) AS DECLARE N

26、ame 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 WHI

27、LE(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(huán)寫(xiě)入數(shù)據(jù) declar

28、e i int set i=1 while i<30 begin insert into test (userid) values(i) set i=i+1 end 小記存儲(chǔ)過(guò)程中經(jīng)常用到的本周，本月，本年函數(shù) Dateadd(wk,datediff(wk,0,getdate(),-1) Dateadd(wk,datediff(wk,0,getdate(),6) Dateadd(mm,datediff(mm,0,getdate(),0) Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate()+1,0) Dateadd(yy,datediff(yy,

29、0,getdate(),0) Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate()+1, 0) 上面的SQL代碼只是一個(gè)時(shí)間段 Dateadd(wk,datediff(wk,0,getdate(),-1) Dateadd(wk,datediff(wk,0,getdate(),6) 就是表示本周時(shí)間段. 下面的SQL的條件部分,就是查詢時(shí)間段在本周范圍內(nèi)的: Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate(),-1) AND Dateadd(wk,datediff(wk,0,getdate(),6) 而在存儲(chǔ)過(guò)程中 select begintime = Dateadd(wk,datediff(wk,0,getdate(),-1) select endtime = Dateadd(wk,datediff(wk,0,getdate(),6) 最后，再補(bǔ)充一些：分組group常用于統(tǒng)計(jì)時(shí)，如分組查總數(shù)：select gender,count(sno) from studentsgroup by gender(查看男女學(xué)生各有多少)注意：從哪種角度分組就從哪列"group by&q