insert into city --找出Hotel表中不存在于city表中的城市名 select disTINCT rtrim(ltrim(cityname)) from Hotel e WHERE not EXISTS (SELECT * FROM city eb WHERE eb.cityname=e.cityname)
--------------------------------Insert---------------------------------
-- 多条数据一次insert插入
INSERT INTO table1
SELECT '张三1','aaa','90' union all
SELECT '张三2','90' union all
SELECT '张三3','90'
/*
INSERT INTO SELECT语句
语句形式为：Insert into Table2(field1,field2,...) select value1,value2,... from Table1
要求目标表Table2必须存在，由于目标表Table2已经存在，所以我们除了插入源表Table1的字段外，还可以插入常量。示例如下：
INSERT INTO SELECT语句复制表数据
*/
--1.创建测试表
create TABLE Table1
(
a varchar(10),b varchar(10),c varchar(10),CONSTRAINT [PK_Table1] PRIMARY KEY CLUSTERED
(
a ASC
)
) ON [PRIMARY]
create TABLE Table2
(
a varchar(10),d int,CONSTRAINT [PK_Table2] PRIMARY KEY CLUSTERED
(
a ASC
)
) ON [PRIMARY]
GO
--2.创建测试数据
Insert into Table1 values('赵','asds','90')
Insert into Table1 values('钱','100')
Insert into Table1 values('孙','80')
Insert into Table1 values('李',null)
GO
select * from Table2
--3.INSERT INTO SELECT语句复制表数据
Insert into Table2(a,c,d) select a,5 from Table1
GO
--4.显示更新后的结果
select * from Table2
GO
/* 结果
a c d
李 NULL 5
钱 100 5
孙 80 5
赵 90 5
*/
--5.删除测试表
drop TABLE Table1
drop TABLE Table2
/*
SELECT INTO FROM语句
语句形式为：SELECT vale1,value2 into Table2 from Table1
要求目标表Table2不存在，因为在插入时会自动创建表Table2，并将Table1中指定字段数据复制到Table2中。示例如下：
SELECT INTO FROM创建表并复制表数据
*/
--1.创建测试表
create TABLE Table1
(
a varchar(10),CONSTRAINT [PK_Table1] PRIMARY KEY CLUSTERED
(
a ASC
)
) ON [PRIMARY]
GO
--2.创建测试数据
Insert into Table1 values('赵',null)
GO
--3.SELECT INTO FROM语句创建表Table2并复制数据
select a,c INTO Table2 from Table1
GO
--4.显示更新后的结果
select * from Table2
GO
/*
a c
李 NULL
钱 100
孙 80
赵 90
*/
--5.删除测试表
drop TABLE Table1
drop TABLE Table2
-- 根据表Adjustment中的记录删除Emp_Bak中对应的数据 DELETE Emp_Bak E WHERE EXISTS ( SELECT 'X' FROM Adjustment A WHERE E.Emp_Id = A.Emp_Id ) DELETE Emp_Bak E WHERE Emp_Id IN ( SELECT A.Emp_Id FROM Adjustment A WHERE E.Emp_Id = A.Emp_Id ) --103,ORACLE 中删除表Emp_Bak中重复数据 --JOIN DELETE Emp_Bak D WHERE ROWID > ( SELECT MIN(ROWID) FROM Emp_Bak R WHERE D.Emp_Id = R.Emp_Id ) --NOT IN DELETE Emp_Bak D WHERE ROWID NOT IN ( SELECT MIN(ROWID) FROM Emp_Bak R GROUP BY R.Emp_Id ) --104,sql SERVER 删除重复数据 分三步 首先将非重复数据存储到临时表,然后清空原数据表,最后将临时表数据存回原数据表 --STEP01 SELECT disTINCT Emp_id,Emp_Name,Dept_id,Mobile,Ext,Salary,Email,Date_Update INTO #Emp_Bak FROM Emp_Bak --STEP02 TruncATE TABLE Emp_Bak --STEP03 INSERT INTO Emp_Bak SELECT Emp_id,GETDATE() Date_Create -- FROM #Emp_Bak ------------------------------4.5------------------------------------ --105,ORACLE,删除大量数据时 可能导致数据库事务日志文件急剧扩展,甚至无法继续进行事务处理等问题,可用分批删除数据方法 DECLARE n NUMBER; BEGIN LOOP EXIT WHEN n=0; DELETE EMP_BAK WHERE ROWNUM<=5 AND Dept_Id Like 'I%'; n :=sql%rOWCOUNT; DBMS_OUTPUT.PUT_LINE( n ); COMMIT; END LOOP; END; --105,sql SERVER,WHILE (@@ROWCOUNT>0) BEGIN DELETE TOP(5) FROM Emp_Bak WHERE Dept_Id Like 'I%' END -------------------------------- ------------------------------5.1------------------------------------ --117 SELECT TO_CHAR(DATE'-4712-01-01','J') "JDay(Base)",TO_CHAR(DATE'2010-01-01','J') "JDay",(TO_CHAR(DATE'2010-01-01','J') -TO_CHAR(DATE'-4712-01-01','J'))/365.25 Diff FROM DUAL --117 SELECT DATE'2010-03-17' Today,TIMESTAMP '2010-3-17 8:28:40' Now FROM DUAL ------------------------------5.4------------------------------------ --124,ORACLE SELECT NVL(A,'新值') "test1.A",COALESCE(A,'新值')"test1.B",B,C) "test2.A",NVL(A,NVL(B,C)) "test2.B" FROM ( SELECT NULL A,NULL B,'非NULL' C FROM DUAL ) --124,sql SERVER SELECT ISNULL(A,'新值') "test1.A",'新值') "test1.B",C) "test2.A",ISNULL(A,ISNULL(B,C)) "test2.B" FROM ( SELECT NULL A,'非NULL' C ) A --125 --sql SERVER SELECT VAL,NULLIF(VAL,0) "NULLIF(VAL,0)" FROM ( SELECT 0 VAL --FROM DUAL UNION ALL SELECT 20 VAL --FROM DUAL ) A --ORACLE SELECT VAL,0)" FROM ( SELECT 0 VAL FROM DUAL UNION ALL SELECT 20 VAL FROM DUAL ) A
--mssql去空格 SELECT REPLACE(REPLACE(REPLACE(REPLACE(CAST('abc def ghi cd e' AS VARCHAR),CHAR(13) + CHAR(10),''),CHAR(13),CHAR(10),' ','')
-- 查询table1中 city相同数目大于1的 且text字段为空 select * from table1 where city in (select city from table1 group by city having count(*)>1) and text is null
--sql：删除重复数据，只保留一条 --在几千条记录里,存在着些相同的记录,如何能用sql语句,删除掉重复的呢 --1、查找表中多余的重复记录，重复记录是根据单个字段（peopleId）来判断 select * from people where peopleId in (select peopleId from people group by peopleId having count(peopleId) > 1) --2、删除表中多余的重复记录，重复记录是根据单个字段（peopleId）来判断，只留有rowid最小的记录 delete from people where peopleName in (select peopleName from people group by peopleName having count(peopleName) > 1) and peopleId not in (select min(peopleId) from people group by peopleName having count(peopleName)>1) --3、查找表中多余的重复记录（多个字段） select * from vitae a where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*) > 1) --4、删除表中多余的重复记录（多个字段），只留有rowid最小的记录 delete from vitae a where (a.peopleId,seq having count(*) > 1) and rowid not in (select min(rowid) from vitae group by peopleId,seq having count(*)>1) --5、查找表中多余的重复记录（多个字段），不包含rowid最小的记录 select * from vitae a where (a.peopleId,seq having count(*)>1) --6.消除一个字段的左边的第一位： update tableName set [Title]=Right([Title],(len([Title])-1)) where Title like '村%' --7.消除一个字段的右边的第一位： update tableName set [Title]=left([Title],(len([Title])-1)) where Title like '%村' --8.假删除表中多余的重复记录（多个字段），不包含rowid最小的记录 update vitae set ispass=-1 where peopleId in (select peopleId from vitae group by peopleId,seq having count(*) > 1) and seq in （select seq from vitae group by peopleId,seq having count(*) > 1） and rowid not in (select min(rowid) from vitae group by peopleId,seq having count(*)>1)
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