sql语句进阶教程（学习sql这一篇就够了）

char

nchar

varchar

nvarchar

1
2

SELECT [ last name]
FROM Customers

1
23
4
5
6

Select -1>选择列,-2>distinct,-3>top
1>…From 表
2>…Where 条件
3>…Group by 列
4>…Having 筛选条件
6>…Order by 列

1
23
4
5
6

INSERT INTO tablename
(columnlist)
VALUES
(RowValues1)
(RowValues2)
(repeat any number of times)

1
23

UPDATE  table
SET column1=expression1,column2=expression2(repeat any number of times)
WHERE condition

1
23

DELETE
FROM table
WHERE condition

1
23
4

SELECT
COUNT（*）
FROM table
WHERE condition

1

DELETE FROM table

1

TRUNCATE TABLE table

1
2

SELECT '直接量' AS `类型`,firstname,lastname
FROM `customers` ;

1
2

SELECT  num*price AS total
FROM orders

1
2

SELECT  firstname+' '+lastname AS 'fullname'
FROM users

1
23

SELECT OrderID,FirstName,LastName,
CONCAT(FirstName,' ',LastName) AS 'fullname'
FROM orders

1
2

SELECT firstname AS fn
FROM customers

1
2

SELECT firstname
FROM customers AS cu

1
2

SELECT
SUBSTRING('thewhitegoat',4,5) AS 'The Answer'

1

SELECT GETDATE()

1

DATEPART(datepart,DateValue)

1

DATEDIFF(datepart1,startdate1,startdate2)

1

DATEDIFF(enddate,startdate)

1

ROUND(numericvalue,decimalpalaces)

1

RAND([seed])

1

SELECT RAND() AS 'Random Value'

1

SELECT ROUND(PI(),2)

1

CAST(expression AS DateType)

1
23

SELECT
'2009-04-11' AS 'Original Date',
CAST('2009--04-11' AS DATETIME) AS 'Converted Date'

1
23

SELECT Description,
ISNULL(Color,'Unknown') AS 'Color'
FROM Products

1
23

SELECT columnlist
FROM tablelist
ORDER BY columnlist

1
23

SELECT columnlist
FROM tablelist
ORDER BY columnlist ASC

1
23

SELECT columnlist
FROM tablelist
ORDER BY columnlist DESC

1
23
4
5

SELECT
FirstName,
LastName
FROM Customers
ORDER BY LastName, FirstName

1
23

SELECT LastName+','+FirstName AS 'Name'
FROM Customers
ORDER BY Name

1
23

SELECT FirstName,LastName
FROM Customers
ORDER BY LastName+FirstName AS 'Name'

1
23
4
5

SELECT
column1,
column2,
CaseExpression
FROM table

1
23
4
5
6
7

SELECT
CASE ColumnOrExpression
WHEN value1 THEN result1WHEN value2 THEN result2
(repeat WHEN-THEN any number of times)
[ELSE  DefaultResult]
END

1
23
4
5
6
7
8

SELECT
CASE CategoryCode
WHEN 'F' THEN 'Fruit'
WHEN 'V' THEN 'Vegetable'
ELSE 'other'
END AS 'Category',
ProductDescription As 'Description'
FROM Products

1
23
4
5
6
7

SELECT
CASE
WHEN condition1 THEN result1WHEN condition2 THEN result2
(repeat WHEN-THEN any number of times)
[ELSE  DefaultResult]
END

1
23
4
5
6

Select -1>选择列,-2>distinct,-3>top
1>…From 表
2>…Where 条件
3>…Group by 列
4>…Having 筛选条件
6>…Order by 列

1
23
4

SELECT
TOP Number
Columnlist
FROM table

1
23
4
5
6
7

SELECT
TOP1Title AS 'Book Title',
CurrentMonthSales AS 'Quantuty Sold'
FROM Books
WHERE Author='Shakespeare'
ORDER BY CurrentMonthSales DESC

1
23
4

SELECT userid,name,phone
FROM users
WHERE age<18
OR age>60

1
23
4
5
6
7

SELECT CustomerName,
Sate,
QuantityPurchased
FROM Orders
WHERE State ='IL'
OR State='CA'
AND QuantityPurchased>8

1
2

State= 'CA'
AND QuantityPurchased>8

1
23
4
5
6
7

SELECT CustomerName,
Sate,
QuantityPurchased
FROM Orders
WHERE (State ='IL'
OR State='CA')
AND QuantityPurchased>8

1
23

SELECT CustomerName,State
FROM Orders
WHERE NOT (State='IL' OR Sate='NY')

1
23
4
5

SELECT CustomerName,
Sate,
QuantityPurchased
FROM Orders
WHERE QuantityPurchased BETWEEN 8 AND 10

1
23
4

SELECT *
FROM Orders
WHERE State='IL'
OR State='CA'

1
23

SELECT *
FROM Orders
WHERE State IN ('IL','CA')

1
23
4

SELECT *
FROM Products
WHERE weight=0
OR weight IS NULL

1
23

SELECT *
FROM Products
WHERE ISNULL(weight,0)=0

1
23
4
5

SELECT
FirstName,
LastName
FROM Actors
WHERE FirstName LIKE '[CM]ARY'

1
2

SELECT DISTINCE name,age
FROM users

1
23
4
5

SELECT
AVG(Grade) AS 'Average Quiz Score'
MIN(Grade) AS 'Minimum Quiz Score'
FROM Grades
WHERE GradeType='Quiz'

1
23
4

SELECT
COUNT(*) AS 'Count of Homework Rows'
FROM Grades
WHERE GradeType='HomeWork'

1
23
4

SELECT
COUNT(Grades) AS 'Count of Homework Rows'
FROM Grades
WHERE GradeType='HomeWork'

1
23

SELECT
COUNT(DISTINCT FeeType) AS 'Number of Fee Types'
FROM Fees

1
23
4
5
6

SELECT
GradeType AS 'Grade Type',
AVG(Grade)AS 'Average Grade'
FROM Grades
GROUP BY GradeType
ORDER BY GradeType

1
23
4
5
6

SELECT
GradeType AS 'Grade Type',
AVG(ISNULL(Grade,0))AS 'Average Grade'
FROM Grades
GROUP BY GradeType
ORDER BY GradeType

1
23
4
5
6
7
8

SELECT
Name,
AVG(ISNULL(Grades,0)) AS 'Average Grades'
FROM Grades
WHERE GradeType='A'
GROUP BY Name
HAVING AVG(ISNULL(Grades,0))>70
ORDER BY Name

1
23
4
5
6
7
8
9

SELECT
Name,
GradeType,
AVG(ISNULL(Grades,0)) AS 'Average Grades'
FROM Grades
WHERE GradeType='A'
GROUP BY Name,GradeType
HAVING AVG(ISNULL(Grades,0))>70
ORDER BY Name

1
23
4

SELECT name,age,orderid
FROM A,B
WHERE A.userid=B.userid
AND orderid=1

1
23
4
5

SELECT name,age,orderid
FROM A
INNER JOIN B
ON A.userid=B.userid
AND orderid=1

1
23
4
5

SELECT name,age,orderid
FROM A
LEFT JOIN B
ON A.userid=B.userid
AND orderid=1

1
23
4

SELECT A.name,B.name as ManagerName
FROM worker as A
LEFT JOIN worker as B
ON A.managerid=B.id

1
23

CREATE VIEW ViewName AS
SelectStatement
[WITH CHECK OPTION]

1

DROP VIEW ViewName

1
2

ALTER VIEW ViewName AS
SelectStatement

1
2

CREATE INDEX Index2
ON MyTable (ColumnFour)

1
2

DROP INDX Index2
ON MyTable