查看 SQL Server 中所有數據庫的信息
select * from sysdatabases
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查看當前使用的數據庫中所有表信息
use Northwind
select * from sysobjects where type='U'
select * from sysobjects where type not in('U','S','SQ','IT','D') --當前使用的數據庫中所有表約束
exec sp_help Categories --查看指定表結構
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查詢表的所有數據
select * from Categories --商品種類
select * from Suppliers --供應廠商
select * from Products --商品信息
select * from Customers --客戶信息
select * from Employees --員工信息
select * from Shippers --貨運公司
select * from Orders --訂單信息
select * from OrderDetails --訂單詳情
--delete from OrderDetails --備份測試用
select * from Reports --報表配置
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查詢結果排序
select CategoryName from Categories --默認按首字段值的首字母排序（與MySQL不同，MySQL默認是主鍵排序）
select CategoryName from Categories order by CategoryID --默認編號正序
select CategoryName from Categories order by CategoryID asc --編號正序
select CategoryName from Categories order by CategoryID desc --編號倒序
select * from OrderDetails where OrderID in(10248,10249) order by OrderID asc,ProductID asc --按多列排序1
select * from OrderDetails where OrderID in(10248,10249) order by OrderID asc,ProductID desc --按多列排序2
select * from OrderDetails where OrderID in(10248,10249) order by OrderID desc,ProductID asc --按多列排序3
select * from OrderDetails where OrderID in(10248,10249) order by OrderID desc,ProductID desc --按多列排序4
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指定條數查詢
select top 2 * from Categories order by CategoryID --頭兩行數據(排序必要)
select top 2 * from Categories where CategoryID not in(select top 2 CategoryID from Categories) order by CategoryID --第二行後兩行數據
select top 2 CategoryID from Categories order by CategoryID desc --倒數兩行數據
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分頁查詢
每頁顯示3條。
想法一
select COUNT(*) from Categories -- 8/3=2···2，最後一頁餘2條數據
select top 3 * from (select top (1*3) * from Categories order by CategoryID) Tab order by CategoryID desc --分頁第一頁，每頁3條
select top 3 * from (select top (2*3) * from Categories order by CategoryID) Tab order by CategoryID desc --分頁第二頁，每頁3條
select top (8%3) * from (select top (3*3) * from Categories order by CategoryID) Tab order by CategoryID desc --分頁第三頁，每頁3條
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想法二(正序)
--select top PerPage * from Categories where CategoryID not in(select top ((NowPage-1)*PerPage) CategoryID from Categories order by CategoryID) order by CategoryID
select top 3 * from Categories where CategoryID not in(select top (0*3) CategoryID from Categories order by CategoryID) order by CategoryID
select top 3 * from Categories where CategoryID not in(select top (1*3) CategoryID from Categories order by CategoryID) order by CategoryID
select top 3 * from Categories where CategoryID not in(select top (2*3) CategoryID from Categories order by CategoryID) order by CategoryID
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想法二(倒序)
select top 3 * from Categories where CategoryID not in(select top (0*3) CategoryID from Categories order by CategoryID desc) order by CategoryID desc
select top 3 * from Categories where CategoryID not in(select top (1*3) CategoryID from Categories order by CategoryID desc) order by CategoryID desc
select top 3 * from Categories where CategoryID not in(select top (2*3) CategoryID from Categories order by CategoryID desc) order by CategoryID desc
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查詢字段指定別名
select CategoryID,CategoryName from Categories --查詢指定列
select CategoryID,CategoryName as 種類名稱 from Categories --指定列別名1
select CategoryID,CategoryName 種類名稱 from Categories --指定列別名2
select CategoryID,種類名稱=CategoryName from Categories --指定列別名3
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集合函數
select count(*) 記錄總數 from Categories --計算總數
select UnitPrice,UnitPrice+10 結果值 from OrderDetails --查詢結果計算
select max(CategoryID) from Categories --求一列的最大值
select min(CategoryID) from Categories --求一列的最大值
select avg(UnitPrice) 平均價格 from Products --求所有商品的平均價格
select * from Products --求所有商品的平均價格
--select UnitPrice from Products where ProductID<=3 --查詢指定商品的價格
select avg(UnitPrice) from Products where ProductID<=3 --求指定商品的平均價格
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函數查詢
select * from Categories where len(CategoryName)=3 --根據字段長度查詢
select * from Categories where len(PictureFile)=7 --根據字段長度查詢
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條件查詢
select * from Categories where CategoryID=2
select * from Categories where CategoryID<>2
select * from Categories where CategoryID!=2
select * from Categories where CategoryID in(2,4,6)
select * from Categories where CategoryID not in(2,4,6)
select * from Categories where CategoryID>3
select * from Categories where CategoryID>=3 and CategoryID<6
select * from Categories where CategoryID>=3 and CategoryID<6 and CategoryID<>4
select * from Categories where CategoryID<3 or CategoryID>6
select * from Categories where CategoryID<3 or CategoryID>6 or CategoryID=5
select * from Categories where CategoryID between 3 and 5
select * from Categories where CategoryID not between 3 and 5
select * from Categories where CategoryID not between 3 and 5 and CategoryID not in(1,2)
select * from Suppliers where Fax is null
select * from Suppliers where Fax is not null
select * from Categories where CategoryName='穀類/麥片'
select * from Categories where CategoryName like '[谷,米]類/麥片'
select * from Categories where CategoryName like '^[谷,米]類/麥片'
select * from Categories where CategoryName like '_類/麥片'
select * from Categories where CategoryName like '__類/麥片'
select * from Categories where CategoryName like '%/麥片'
select * from Categories where CategoryName like '穀類/%'
select * from Categories where CategoryName like '%/%'
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通配符：
1. %，包含0個或多個字符的任意字符；
2. _，任何單個字符；
3. []，指定範圍([a-f])或集合([abcd])的任何單個字符；
4. [^]，不屬於指定範圍([a-f])或集合([abcd])的任何單個字符。
日期查詢
select * from Orders where OrderDate='1996-07-04'
select * from Orders where OrderDate>='1996-01-01' and OrderDate<'1997-01-01'
select * from Orders where OrderDate between '1996-01-01' and '1996-12-31 23:59:59'
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分組查詢
select distinct ProductID from OrderDetails --出現過的ProductID（查詢結果不會有重複的值）
select ProductID,count(ProductID) 訂單數量,sum(Quantity) 該類總量 from OrderDetails group by ProductID --按ProductID分組，並求得每種的出現次數，與該種類的數量總和
select ProductID,count(ProductID) 訂單數量,sum(Quantity) 該類總量 from OrderDetails group by ProductID having sum(Quantity)<200 --在上面分組查詢的基礎上添加新的條件
select ProductID,count(ProductID) 訂單數量,sum(Quantity) 該類總量 from OrderDetails group by ProductID having sum(Quantity)<200 and ProductID<>15 --在上面分組查詢的基礎上添加新的條件
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臨時表
select CategoryID,CategoryName,Description into #TempTab1 from Categories where CategoryID between 3 and 5
select * from #TempTab1
drop table #TempTab1
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子查詢
select * from Products where SupplierID in(select SupplierID from Suppliers where City='上海')
select Tab1.CompanyName from (select * from Suppliers where City='上海') as Tab1
select CompanyName from (select * from Suppliers where City='上海') as Tab1
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聯表查詢
select P.CategoryID,C.CategoryName,P.ProductID,P.ProductName,P.QuantityPerUnit,P.UnitPrice,P.UnitsInStock from Products P join Categories C on P.CategoryID=C.CategoryID
select C.CategoryName,P.ProductID,P.ProductName,P.QuantityPerUnit,P.UnitPrice,P.UnitsInStock from Products P join Categories C on P.CategoryID=C.CategoryID
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即使查詢字段裏不存在兩表的 CategoryID，仍可用兩表的 CategoryID 聯表。
連表方式：
1. 交叉連接(cross join)：將兩個表不加任何約束地組合起來，在實際應用中一般沒有意義；
2. 內連接(自然連接)([inner] join)：將交叉連接按照連接條件進行過濾，匹配的才能出現在結果集，通常採用主鍵=外鍵的形式；
3. 外連接：和內連接的不同是，不匹配條件的行也能出現在結果集，對應的空位會被填上NULL，左外連接(left join, left outer join)是對左表不加限制，右外連接(right join, right outer join)是對右表不加限制，全外連接(full join, full outer join)是對左右兩表都不加限制。
合併查詢
select CategoryID,CategoryName from Categories where CategoryID<=4 union select CategoryID,CategoryName from Categories where CategoryID>4 --將兩個或兩個以上的查詢結果合併
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邏輯查詢case
select LastName+FirstName as 姓名,TitleOfCourtesy as 稱謂 from Employees
select LastName+FirstName 姓名,case Gender
when 0 then '女'
when 1 then '男'
end as 性別 from Employees
select LastName+FirstName 姓名,case TitleOfCourtesy
when '女士' then '女孩'
when '先生' then '男孩'
else '未知'
end as 稱謂 from Employees
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select 與 print
print 123
select 123
select 123 as Result
select 123 Result
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邏輯查詢 ifelse，convert 類型轉換
declare @name nvarchar(10) set @name='點心'
if exists(select CategoryName from Categories where CategoryName=@name)
begin
print '存在 '+@name --可用select
declare @id int
select @id=CategoryID from Categories where CategoryName=@name
print 'ID: '+convert(varchar,@id)
end
else print '不存在 '+@name--可用select
if(select CategoryID from Categories where CategoryName='點心')=3 print 'Right' else print 'Wrong'
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時間控制 waitfor
waitfor delay '00:00:03'--等待3秒
select '11'
waitfor time '17:44:03'--等待到具體時間
select '22'
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獲取時間 getdate, datename
select getdate()
select datename(year,getdate())
select datename(month,getdate())
select datename(day,getdate())
select datename(hour,getdate())
select datename(minute,getdate())
select datename(second,getdate())
select datename(millisecond,getdate())
select datename(year,getdate())+'-'+ datename(month,getdate())+'-'+datename(day,getdate())
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循環控制 while
declare @i int set @i=1
while 1=1
begin
if @i<10
begin
print @i
set @i=@i+1
end
else break
end
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視圖查詢
create view Categories_Products as select P.CategoryID,C.CategoryName,P.ProductID,P.ProductName,P.QuantityPerUnit,P.UnitPrice,P.UnitsInStock from Products P join Categories C on P.CategoryID=C.CategoryID
select * from Categories_Products --查詢視圖
exec sp_helptext Categories_Products --查詢視圖的創建語句
exec sp_help Categories_Products --查看視圖結構
create view Categories_Products with encryption as select P.CategoryID,C.CategoryName,P.ProductID,P.ProductName,P.QuantityPerUnit,P.UnitPrice,P.UnitsInStock from Products P join Categories C on P.CategoryID=C.CategoryID --創建視圖並加密，加密後不能使用 exec sp_helptext 查看它的創建語句
alter view Categories_Products with encryption as select P.CategoryID,C.CategoryName,P.ProductID,P.ProductName,P.QuantityPerUnit,P.UnitPrice,P.UnitsInStock from Products P join Categories C on P.CategoryID=C.CategoryID --加密視圖
drop view Categories_Products --刪除視圖
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用視圖修改數據表的數據
若視圖字段來自表達式或常量，則只能進行delete操作；
若視圖字段來自集合函數，則不允許修改操作；
若視圖定義中含group by子句，則不允許修改操作；
若視圖定義中含有distinct短語，則不允許修改操作；
在一個不允許修改操作視圖上定義的視圖，不允許修改操作。
update Categories_Products set ProductName='牛奶2' where ProductID=2
update Categories_Products set ProductName='牛奶' where ProductID=2
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修改與刪除數據
修改與刪除的 where 條件與條件查詢的語法相同。
select * from Categories
update Categories set CategoryName='牛奶2' where CategoryID=2
update Categories set CategoryName='牛奶2',Description='暫無描述' where CategoryID=2
delete from Categories where CategoryID=2
delete from Categories --刪除指定表內全部數據：有刪除記錄，可恢復
truncate table Categories --刪除指定表內全部數據(能重置主鍵ID的遞增起始數爲1)：速度快，無刪除記錄，不可恢復，不可刪除有外鍵的表
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版權聲明：本文爲CSDN博主「petezh」的原創文章，遵循 CC 4.0 BY-SA 版權協議，轉載請附上原文出處鏈接及本聲明。
原文鏈接：https://blog.csdn.net/petezh/article/details/81744922