sql server相關學習sql陳述句

if exists(select * from sys.objects where name='Department' and type='U')
	drop table Department
create table Department
(
	--id identity(x,y) 初始x 自增y，primary key 主鍵
	DepartmentId int primary key identity(1,1),
	--名稱
	DepartmentName nvarchar(50) not null,
	--描述
	DepartmentRemark text


)
--字串
--char(x)  占用x個位元組 ‘ab’=>x個位元組
--varchar(x) 最多占用x個位元組  ‘ab’=>2個（x>2）
--text 長文本
--char text varchar 前面加n;存盤unicode 對中文友好
--例子
--varchar(100) 100個字母或者50個漢字
--nvarchar(100) 100個字母或者100個漢字

--Rank是關鍵字了，所以加上[]
create table [Rank]
(
	--id identity(x,y) 初始x 自增y，primary key 主鍵
	RankId int primary key identity(1,1),
	--名稱
	RankName nvarchar(50) not null,
	--描述
	RankRemark text


)

if exists(select * from sys.objects where name='People' and type='U')
	drop table People

create table People(
	--id identity(x,y) 初始x 自增y，primary key 主鍵
	PeopleId int primary key identity(1,1),
	--部門 references 參考外鍵 參考在部門表的id范圍之內
	DepartmentId int references Department(DepartmentId)not null ,
	--職員
	RankId int references [Rank](RankId)not null,
	--名稱
	PeopleName nvarchar(50) not null,
	--性別 加上約束(check) 默認
	PeopleSex nvarchar(1)default('男') check(PeopleSex='男' or PeopleSex='女')not null,
	--老版本date 新版本有time 加上samll就是表示現在時間 不能表示未來
	PeopleBirth smalldatetime not null,
	--小數的使用 float 可能有誤差 decimal(x,y) 長度x,小數y位
	PeopleSalary decimal(12,2) check(PeopleSalary>=1000 and PeopleSalary<=100000)not null,
	--電話 約束unique 唯一 電話是唯一的
	PeoplePhone varchar(20)unique not null,
	--地址
	PeopleAddress varchar(300),
	--添加時間,獲取當前時間默認值,有一個函式 getdate()
	PeopleAddTime smalldatetime default(getdate()) not null
)

--修改表結構---

--(1)CRUD列
--alter table 表名 add 新列名 資料型別
--添加列 員工表添加郵箱列
alter table People add Mail varchar(200)
--alter table 表名 drop column 列名 
--洗掉列 員工表洗掉郵箱列
alter table People drop column Mail
--alter table 表名 alter column 列名 資料型別
--修改地址為 200
alter table People alter column PeopleAddress varchar(200)

--維護約束---(洗掉 添加)
--洗掉約束
--alter table 表名 drop constraint 約束名
--alter table People drop constraint xxx
--添加約束
--alter table 表名 add constraint 約束名 check(運算式)
--alter table People add constraint psadad check(PeopleSex='男' or PeopleSex='女')
--添加主鍵 唯一 默認 外鍵
--alter table 表名 add constraint 約束名 primary key (列名)


insert into Department(DepartmentName,DepartmentRemark)
values('市場部','..........')

insert into Department(DepartmentName,DepartmentRemark)
values('軟體部','..........')

insert into Department(DepartmentName,DepartmentRemark)
values('企劃部','..........')

insert into Department(DepartmentName,DepartmentRemark)
values('銷售部','..........')
--最好一一對應 如果列順序改變就回值出問題
--一次性插入多行資料

use Mytest
select *from Department
select * from [Rank]
select * from People


--資料crud
--修改
--update 表名 set 列名='xxx' where 條件
--update 表名 set 列名='xxx'， 列名='yyy' where 條件

update Department set DepartmentName='經理部' where DepartmentId=8
update People set PeopleSalary=PeopleSalary+1000 

update People set PeopleSalary=15000 where RankId=3 and PeopleSalary<=15000
update People set PeopleSalary=PeopleSalary*2,PeopleAddress='西京' where PeopleName='關羽7'

--delete drop truncate區別
--drop table xxx 洗掉表物件xxx
--delete from xxx 洗掉表xxx的資料， 即表物件和結構都存在
--truncate table xxx 洗掉資料（清空資料）即表物件和結構都存在

--truncate 清空所有資料，不能有資料， delete 可以洗掉所有資料也可以帶條件洗掉符合條件的資料
--自動編號 1,2,3,4,5
--truncate 編號為：1，2，3，4，5 （重頭開始）
--delete   編號將為6，7，8，9，10（繼續）
--查詢 as可省略 ，distinct()去重，
select PeopleName 姓名 from People
select distinct(PeopleAddress) from People
select PeopleSalary*1.2 加薪后,PeopleSalary 加薪前 from People
--按照 名字長度的前5個查詢
select top 5 PeopleName from People order by len(PeopleName)
--按照 名字長度的前25%查詢
select top 25 percent PeopleName from People order by len(PeopleName)
--按照 名字長度的后25%查詢
select top 25 percent PeopleName from People order by len(PeopleName) desc
--查詢為null的值的單位
select *from People where PeopleAddress is null;
--查詢非空的值 和‘ ’區別 null就是沒填  ‘ ’insert 有欄位但是空白
select *from People where PeopleAddress is not null;
--查詢時間的 1988到2000的
select * from People where PeopleBirth>'1988-8-7' and PeopleBirth<'2000-3-1'

select * from People where PeopleBirth between '1988-8-8'and '2000-3-1'

select * from People where year(PeopleBirth) between 1988  and 2000
--查詢年紀在多少歲的
select PeopleName,year(GETDATE())-YEAR(PeopleBirth) 年齡 from People
--查詢年紀在35歲以下的
select PeopleName,year(GETDATE())-YEAR(PeopleBirth) 年齡 from People where year(GETDATE())-YEAR(PeopleBirth)<35 and PeopleSalary >5000
select* from People where (MONTH(PeopleBirth)=11 and DAY(PeopleBirth)<=22) or (MONTH(PeopleBirth)=12 and DAY(PeopleBirth)<=31)
--子查詢
select *from People where PeopleAddress=
(select PeopleAddress from People where PeopleName='關羽')
--龍 8
--鼠 4
--?? 3
select 2000%12


select *,
case
	when YEAR(PeopleBirth)%12=4 then '鼠'
	when YEAR(PeopleBirth)%12=5 then '牛'
	when YEAR(PeopleBirth)%12=6 then '虎'
	when YEAR(PeopleBirth)%12=7 then '兔'
	when YEAR(PeopleBirth)%12=8 then '龍'
	when YEAR(PeopleBirth)%12=9 then '蛇'
	when YEAR(PeopleBirth)%12=10 then '馬'
	when YEAR(PeopleBirth)%12=11 then '羊'
	when YEAR(PeopleBirth)%12=0 then '猴'
	when YEAR(PeopleBirth)%12=1 then '雞'
	when YEAR(PeopleBirth)%12=2 then '狗'
	when YEAR(PeopleBirth)%12=3 then '豬'
end 生肖
from People


--優化
select *,
case YEAR(PeopleBirth)%12
	when 4 then '鼠'
	when 5 then '牛'
	when 6 then '虎'
	when 7 then '兔'
	when 8 then '龍'
	when 9 then '蛇'
	when 10 then '馬'
	when 11 then '羊'
	when 0 then '猴'
	when 1 then '雞'
	when 2 then '狗'
	when 3 then '豬'
end 生肖
from People

select *from People where PeopleAddress not like '%南%' 

--查詢名字2個字的 第一個字為劉
select * from People where SUBSTRING(PeopleName,1,1)='劉' and LEN(PeopleName)=2
select * from People where SUBSTRING(PeopleName,2,1)='備' and LEN(PeopleName)=2
select *from People where PeoplePhone like '1516%'
--開頭4位是1516 第五位為1或者2 最后一位為9
select *from People where PeoplePhone like '1516[1,2]%9'
--開頭4位是1516 第五位為1到8 最后一位為不為4到8
select *from People where PeoplePhone like '1516[1-8]%[^4-8]'