T-SQL语句之Select(一)

Operator	Description
!=	Tests two expressions not being equal to each other.
!>	Tests that the left condition is not greater than the expression to the right.
!<	Tests that the right condition is not greater than the expression to the right.
<	Tests the left condition as less than the right condition.
<=	Tests the left condition as less than or equal to the right condition.
<>	Tests two expressions not being equal to each other.
=	Tests equality between two expressions.
>	Tests the left condition being greater than the expression to the right.
>=	Tests the left condition being greater than or equal to the expression to the right.
ALL	When used with a comparison operator and subquery, if all retrieved values satisfy the search condition, the rows will be retrieved.
ANY	When used with a comparison operator and subquery, if any retrieved values satisfy the search condition, the rows will be retrieved.
BETWEEN	Designates an inclusive range of values. Used with the AND clause between the beginning and ending values.
CONTAINS	Does a fuzzy search for words and phrases.
ESCAPE	Takes the character used prior to a wildcard character to designate that the literal value of the wildcard character should be searched, rather than use the character as a wildcard.
EXISTS	When used with a subquery, EXISTS tests for the existence of rows in the subquery.
FREETEXT	Searches character-based data for words using meaning, rather than literal values.
IN	Provides an inclusive list of values for the search condition.
IS NOT NULL	Evaluates if the value is NOT null.
IS NULL	Evaluates whether the value is null.
LIKE	Tests character string for pattern matching
NOT BETWEEN	Specifies a range of values NOT to include. Used with the AND clause between the beginning and ending values.
NOT IN	Provides a list of values for which NOT to return rows for.
NOT LIKE	Tests character string, excluding those with pattern matches.
SOME	When used with a comparison operator and subquery, if any retrieved values satisfy the search condition, the rows will be retrieved.

-- Using BETWEEN for Date Range Searches
SELECT SalesOrderID, ShipDate
FROM Sales.SalesOrderHeader
WHERE ShipDate BETWEEN '7/28/2002' AND '7/29/2002'		


--Using Comparisons
SELECT ProductID,Name,StandardCost
FROM Production.Product
WHERE StandardCost < 110.0000


--Checking for NULL Values
SELECT ProductID,Name,Weight
FROM Production.Product
WHERE Weight IS NULL


--Returning Rows Based on a List of Values
SELECT ProductID,Name,Color
FROM Production.Product
WHERE Color IN ('Silver', 'Black', 'Red')


-- Wildcard		Usage
--	  %			Represents a string of zero or more characters.
--    _			Represents a single character.
--   []			Specifies a single character, from a selected range or list.
--   [^]		Specifies a single character not within the specified range.
SELECT ProductID,Name
FROM Production.Product
WHERE Name LIKE 'B%'

SELECT ProductID, Name
FROM Production.Product
WHERE Name LIKE '%/_%' ESCAPE '/'


--Using the ORDER BY Clause
SELECT p.Name,h.EndDate,h.ListPrice
FROM Production.Product p
       INNER JOIN 
			Production.ProductListPriceHistory h 
       ON
			p.ProductID = h.ProductID
ORDER BY p.Name, h.EndDate

SELECT p.Name,h.EndDate,h.ListPrice
FROM Production.Product p
	INNER JOIN 
		Production.ProductListPriceHistory h 
	ON
		p.ProductID = h.ProductID
ORDER BY p.Name DESC, h.EndDate DESC


--Using the TOP Keyword with Ordered Results
SELECT TOP 10 v.Name, v.CreditRating
FROM Purchasing.Vendor v
ORDER BY v.CreditRating DESC, v.Name



--Using the GROUP BY Clause
--	This error is raised because any column that is not used in an aggregate function in the SELECT
--	list must be listed in the GROUP BY clause.
SELECT OrderDate, SUM(TotalDue) TotalDueByOrderDate
FROM Sales.SalesOrderHeader
WHERE OrderDate BETWEEN '7/1/2001' AND '7/31/2001'
GROUP BY OrderDate


--Using GROUP BY ALL
--	In the results returned by the GROUP BY ALL example, notice that 
--	TotalDueByOrderDate was NULL for those order dates not included 
--	in the WHERE clause. This does not mean they have zero rows, but
--	instead, that data is not displayed for them.
SELECT OrderDate,
		SUM(TotalDue) TotalDueByOrderDate
FROM Sales.SalesOrderHeader
WHERE OrderDate BETWEEN '7/1/2001' AND '7/31/2001'
GROUP BY ALL OrderDate



--Selectively Querying Grouped Data Using HAVING
--	The HAVING clause is used after the GROUP BY clause. 
--	The WHERE clause, in contrast, is used to qualify
--	the rows that are returned before the data is aggregated 
--	or grouped. HAVING qualifies the aggregated
--	data after the data has been grouped or aggregated.
SELECT s.Name,
		COUNT(w.WorkOrderID) Cnt
FROM Production.ScrapReason s
	INNER JOIN 
		Production.WorkOrder w 
	ON
		s.ScrapReasonID = w.ScrapReasonID
GROUP BY s.Name
HAVING COUNT(*)>50


--Using DISTINCT to Remove Duplicate Values
SELECT DISTINCT HireDate
FROM HumanResources.Employee


--Using DISTINCT in Aggregate Functions
SELECT AVG(DISTINCT ListPrice)
FROM Production.Product


--Using Column Aliases
SELECT Color AS 'Grouped Color',
		AVG(DISTINCT ListPrice) AS 'Average Distinct List Price',
		AVG(ListPrice) 'Average List Price'
FROM Production.Product
GROUP BY Color

--Performing String Concatenation
SELECT 'The ' +
		p.Name +
		' is only ' +
		CONVERT(varchar(25),p.ListPrice) +'!'
FROM Production.Product p
WHERE p.ListPrice between 100 AND 120
ORDER BY p.ListPrice


--Creating a Comma Delimited List Using SELECT
DECLARE @Shifts varchar(20)
SET @Shifts = ''
SELECT @Shifts = @Shifts + s.Name + ','
FROM HumanResources.Shift s
ORDER BY s.EndTime
SELECT @Shifts

--Using the INTO Clause
SELECT CustomerID,
		Name,
		SalesPersonID,
		Demographics
INTO Store_Archive
FROM Sales.Store


--Using Subqueries to Check for the Existence of Matches
SELECT DISTINCT s.PurchaseOrderNumber
FROM Sales.SalesOrderHeader s
WHERE EXISTS ( SELECT SalesOrderID
FROM Sales.SalesOrderDetail
WHERE UnitPrice BETWEEN 1000 AND 2000 AND
		SalesOrderID = s.SalesOrderID)
		
SELECT SalesPersonID,
		SalesQuota CurrentSalesQuota
FROM Sales.SalesPerson
WHERE SalesQuota 
		IN
		(SELECT MAX(SalesQuota)
		FROM Sales.SalesPerson)
		
		
--Using INNER Joins
SELECT p.Name,
		s.DiscountPct
FROM Sales.SpecialOffer s
		INNER JOIN Sales.SpecialOfferProduct o 
		ON s.SpecialOfferID = o.SpecialOfferID
		INNER JOIN Production.Product p 
		ON o.ProductID = p.ProductID
WHERE p.Name = 'All-Purpose Bike Stand'


--Using OUTER Joins
SELECT s.CountryRegionCode,
		s.StateProvinceCode,
		t.TaxType,
		t.TaxRate
FROM Person.StateProvince s
	INNER JOIN Sales.SalesTaxRate t 
	ON s.StateProvinceID = t.StateProvinceID
	
SELECT s.CountryRegionCode,
		s.StateProvinceCode,
		t.TaxType,
		t.TaxRate
FROM Person.StateProvince s
	LEFT OUTER JOIN Sales.SalesTaxRate t 
	ON s.StateProvinceID = t.StateProvinceID
	

--Using CROSS Joins: S.Num * T.Num
SELECT s.CountryRegionCode,
		s.StateProvinceCode,
		t.TaxType,
		t.TaxRate
FROM Person.StateProvince s
	CROSS JOIN Sales.SalesTaxRate t
	
	
--Performing Self-Joins
SELECT e.EmployeeID,
		e.Title,
		m.Title AS ManagerTitle
FROM HumanResources.Employee e
		LEFT OUTER JOIN HumanResources.Employee m 
		ON e.ManagerID = m.EmployeeID


--Using Derived Tables
SELECT DISTINCT s.PurchaseOrderNumber
FROM Sales.SalesOrderHeader s
	INNER JOIN (SELECT SalesOrderID
			FROM Sales.SalesOrderDetail
			WHERE UnitPrice BETWEEN 1000 AND 2000) d 
	ON
	  s.SalesOrderID = d.SalesOrderID
	  
	  
--Combining Result Sets with UNION
--	The UNION operator is used to append the results of two or more SELECT statements into a single
--	result set. Each SELECT statement being merged must have the same number of columns, with the
--	same or compatible data types in the same order, as this example demonstrates:
SELECT SalesPersonID, GETDATE() QuotaDate, SalesQuota
FROM Sales.SalesPerson
WHERE SalesQuota > 0
UNION
SELECT SalesPersonID, QuotaDate, SalesQuota
FROM Sales.SalesPersonQuotaHistory
WHERE SalesQuota > 0
ORDER BY SalesPersonID DESC, QuotaDate DESC