SqlServer语句收集
1 临时表
--创建临时表 数据库重启后表#a1会消失
create table #a1
(
col1 int,
col2 int
)
select * from #a1
--创建临时表 改表只存在与当前的session
create table ##a2
(
col1 int,
col2 int
)
2 从两个表中select
create table ##b1
(
col1 int
)
create table ##b2
(
col2 int
)
insert ##b1 values(1)
insert ##b1 values(2)
insert ##b1 values(3)
insert ##b2 values(2)
insert ##b2 values(1)
select col1,col2 from ##b1,##b2
/*
得到的结果是2*3=6条记录
col1 col2
1 2
2 2
3 2
1 1
2 1
3 1
*/
3 只保留时间的日期部分
select convert(varchar(10), getdate(),120)
/*
得到如下结果
2007-03-15
*/
4 时间的小时,分秒部分归零
declare @date datetime
set @date=getdate()
select DATEADD(day, DATEDIFF(day,0,@date), 0)
/*
得到如下结果
2007-03-15 00:00:00.000
*/
5 读取第n条记录以后的记录
declare @n int
set @n=5
select * from 表 where id not in (select top (@n) id from 表)
6 如何得到时间段内的所有日期
给出起始时间和结束时间,然后的到之间的全部日期
例如其时日期为2007-1-1,结束日期为2007-1-5
得到如下结果
2007-1-1
2007-1-2
2007-1-3
2007-1-4
2007-1-5
给出两个方法
1
create table #
(
col datetime
)
go
declare @begintime datetime
declare @endtime datetime
declare @day int
set @begintime=cast('2007-1-1' as datetime)
set @endtime =cast('2007-1-5' as datetime)
select @day=DATEDIFF(day, @begintime, @endtime)
while @day>=0
begin
insert into # select dateadd(day,@day,@begintime)
set @day=@day-1
end
select * from #
drop table #
2
Declare @StartDate DateTime, @EndDate DateTime
Select @StartDate = '2007-1-1' , @EndDate = '2007-1-5'
Select Top 100 Identity(Int, 0, 1) As ID Into #T from Sysobjects A, Sysobjects B
Select
DateAdd(dd, ID, @StartDate) As [Date]
From #T
Where ID <= DateDiff(dd, @StartDate, @EndDate)
Drop table #T
６Full Join
a,b两表数据如下
a:
name chinese
张三 60
李四 70
b:
name english
张三 90
王五 80
希望查询的结果如下:
name chinese english
张三 60 90
李四 70 null
王五 null 90
sql语句如下
Select
IsNull(A.name, B.name) As name,
IsNull(A.chinese, 0) As chinese,
IsNull(B.english, 0) As english
From
A
Full Join
B
On A.name = B.name
７ 条件语句的放置位置
语句如下:
select a.id,b.id from a
left join b on a.id=b.id and b.date>'2007-1-1'
select a.id,b.id from a
left join b on a.id=b.id
where b.date>'2007-1-1'
两个语句的结果是不一样的,第一个语句是现对b表进行筛选,然后再和a表join
而第二个语句是先join再对整体的join后的结果进行率选,所有可能得到比第一种少的结果集
８ 对重复记录进行操作
1 去除重复项
select * from table1 where col1 not in
(
select col1 from table1 group by col1 having count(col1)>1
)
2 只筛选出重复项
select * from table1 where col1 in
(
select col1 from table1 group by col1 having count(col1)>1
)
９ 判断是否为数字
ISNUMERIC(expression)
数字返回1
非数字返回0
10 得到存储过程内容
select text from syscomments where id=object_id('procName')
11 删除所有的存储过程
--使用游标
declare @delProc nvarchar(200)
declare @dll nvarchar(4000)
set @dll=''
set @delProc='drop proc '
declare @procName nvarchar(100)
DECLARE proc_cur CURSOR FOR
SELECT name FROM sysobjects where xtype='p';
OPEN proc_cur;
FETCH NEXT FROM proc_cur
into @procName
WHILE @@FETCH_STATUS = 0
BEGIN
set @dll=@dll+ ' '+ @delProc+@procName
FETCH NEXT FROM proc_cur
into @procname
END;
CLOSE proc_cur;
DEALLOCATE proc_cur;
print @dll
12 事务
BEGIN TRY
BEGIN TRAN
INSERT INTO table1 (i,col1,col2)
VALUES (1,'First row','First row');
INSERT INTO table1 (i,col1,col2)
VALUES (2,NULL,'Second row');
INSERT INTO table1 (i,col1,col2)
VALUES (3,'Third row','Third row');
COMMIT TRAN;
END TRY
BEGIN CATCH
ROLLBACK TRAN
END CATCH;
13 外键约束
create table company
(
id int identity(1,1),
name nvarchar(20) unique
)
create table product
(
id int identity(1,1),
companyid int,
name nvarchar(20) ,
unitprice money,
unique(companyid,name)
)
--添加外键约束
alter table product add constraint fk_company_prodcut
foreign key(companyid)
references company(id) on UPDATE CASCADE ON DELETE CASCADE
----删除
alter table product drop constraint fk_company_prodcut
14 触发器
USE tempdb
GO
CREATE TABLE TZ (
Z_id int IDENTITY(1,1)PRIMARY KEY,
Z_name varchar(20) NOT NULL)
CREATE TABLE TY (
Y_id int IDENTITY(100,5)PRIMARY KEY,
Y_name varchar(20) NULL)
/*Create the trigger that inserts a row in table TY
when a row is inserted in table TZ*/
CREATE TRIGGER Ztrigsssss
ON TZ
FOR INSERT,update,delete AS
BEGIN
INSERT TY VALUES ('')
END
15 备份数据库
use master
backup database databaseName to disk='c:\1.bak'
16字符串拆分
将类似 1,2,3,4,5,6的字符串进行转秩
1
2
3
4
5
6
CREATE function StrSplit(@str nvarchar(4000),@splitSign nvarchar(10))
returns @table table (itemid int identity(1,1),tempStr nvarchar(3000))
as
begin
while charindex(@splitSign,@str)>0
begin
insert into @table (tempStr)
select left(@str,charindex(@splitSign,@str)-1)
select @str=stuff(@str,1,charindex(@splitSign,@str)+len(@splitSign)-1,'')
end
insert @table (tempStr) select @str
return
end
17 DBCC命令
DBCC TRACEON(3604)
DBCC PAGE
DBCC CheckConstraints(tableName)--检查表中不符合约束的数据
DBCC ShrinkDatabase
DBCC ShrinkFile
18 Query the DB size
SELECT type_desc ,Sum(Size) FROM sys.database_Files Group by type_desc
CREATE TABLE sp_table_pages
(PageFID tinyint,
PagePID int,
IAMFID tinyint,
IAMPID int,
ObjectID int,
IndexID tinyint,
PartitionNumber tinyint,
PartitionID bigint,
iam_chain_type varchar(30),
PageType tinyint,
IndexLevel tinyint,
NextPageFID tinyint,
NextPagePID int,
PrevPageFID tinyint,
PrevPagePID int,
Primary Key (PageFID, PagePID));
TRUNCATE TABLE sp_table_pages;
INSERT INTO sp_table_pages
EXEC ('dbcc ind ( AdventureWorks, [Sales.SalesOrderDetail], -1)' );GAP
代码
create table gaps(col int)
insert gaps
values(-1),(-3),(-2),(1),(2),(3),(4),
(100),(101),(103)
go
select COL+1 as gap_start,(select MIN(col) from gaps g2 where g2.col>g1.col)-1 as gap_end
from gaps g1 where not exists
(
select 1 from gaps g2 where g2.col=g1.col+1
)
and col<(select MAX(col) from gaps)
go
select col+1 as gap_start,(select MIN(col) from gaps g4 where g4.col>g3.col)-1 as gap_end
from gaps g3 where col not in(
select g1.col from gaps g1 inner join gaps g2 on g2.col=g1.col+1
)
and col<(select MAX(col) from gaps)
xp_readerrorlog
从错误日志中查找指定关键字的信息declare @end datetime
set @end=getdate()
declare @keywords nvarchar(100)
set @keywords='replication'
exec xp_ReadErrorLog 0,1, @keywords,null, '2011-02-16 16:41:11.817',@end,'desc'
