SQL 系列教程(二)

目录

SQL DELETE 语句

DELETE 语句

演示数据库

DELETE 实例

删除所有行

SQL TOP, LIMIT, ROWNUM 子句

TOP 子句

演示数据库

SQL TOP、LIMIT 和 ROWNUM 示例

SQL TOP PERCENT 实例

添加WHERE子句

SQL MIN() 和 MAX() 函数

MIN() 和 MAX() 函数

演示数据库

MIN() 实例

MAX() 实例

SQL COUNT(), AVG() 和 SUM() 函数

COUNT(), AVG() 和 SUM() 函数

演示数据库

COUNT() 实例

AVG() 实例

演示数据库

SUM() 实例

SQL LIKE 操作符

SQL LIKE 操作符

演示数据库

LIKE 操作符实例

SQL 通配符

SQL 通配符

演示数据库

使用 % 通配符

使用 _ 通配符

使用 [charlist] 通配符

使用 [!charlist] 通配符

SQL IN 操作符

SQL IN 操作符

演示数据库

IN 操作符实例

SQL BETWEEN 操作符

SQL BETWEEN 操作符

演示数据库

BETWEEN 实例

NOT BETWEEN 实例

带有 IN 的 BETWEEN 操作符实例

带有文本值的 BETWEEN 操作符实例

带有文本值的 NOT BETWEEN 操作符实例

示例表

带有日期值的 BETWEEN 操作符实例

SQL 别名

SQL 别名

演示数据库

Alias 实例: 使用一个列名别名

Alias 实例: 使用表名称别名

SQL 联接

SQL JOIN

不同类型的 SQL JOIN


SQL DELETE 语句

DELETE 语句

DELETE 语句用于删除表中的记录。

【DELETE 语法】

DELETE FROM table_name WHERE condition;

注: 请注意 SQL DELETE 语句中的 WHERE 子句!WHERE 子句规定哪条记录或者哪些记录需要删除。如果您省略了 WHERE 子句,所有的记录都将被删除!

演示数据库

以下是从示例数据库的 "客户(Customers)" 表中查询的内容:

CustomerID CustomerName ContactName Address City PostalCode Country
1
 
Alfreds Futterkiste Maria Anders Obere Str. 57 Berlin 12209 Germany
2 Ana Trujillo Emparedados y helados Ana Trujillo Avda. de la Constitución 2222 México D.F. 05021 Mexico
3 Antonio Moreno Taquería Antonio Moreno Mataderos 2312 México D.F. 05023 Mexico
4
 
Around the Horn Thomas Hardy 120 Hanover Sq. London WA1 1DP UK
5 Berglunds snabbköp Christina Berglund Berguvsvägen 8 Luleå S-958 22 Sweden

DELETE 实例

以下 SQL 语句从 客户(customer) 表中删除客户 "Alfreds Futterkiste"

【实例】

DELETE FROM Customers WHERE CustomerName='Alfreds Futterkiste';

客户(Customers) 表现在如下所示:

CustomerID CustomerName ContactName Address City PostalCode Country
2 Ana Trujillo Emparedados y helados Ana Trujillo Avda. de la Constitución 2222 México D.F. 05021 Mexico
3 Antonio Moreno Taquería Antonio Moreno Mataderos 2312 México D.F. 05023 Mexico
4
 
Around the Horn Thomas Hardy 120 Hanover Sq. London WA1 1DP UK
5 Berglunds snabbköp Christina Berglund Berguvsvägen 8 Luleå S-958 22 Sweden

删除所有行

可以在不删除表的情况下删除所有的行。这意味着表的结构、属性和索引都是完整的:

DELETE FROM table_name;

以下 SQL 语句删除 "Customers" 表中的所有行,而不删除该表:

【实例】

DELETE FROM Customers;

SQL TOP, LIMIT, ROWNUM 子句

TOP 子句

TOP 子句用于规定要返回的记录的数目。

TOP 子句对于包含数千条记录的大型表很有用。返回大量记录可能会影响性能。

注: 并非所有数据库系统都支持 SELECT TOP子句。MySQL 使用 LIMIT,而 Oracle 使用 ROWNUM。

【SQL Server / MS Access 的语法:】

SELECT TOP number|percent column_name(s)
FROM table_name
WHERE condition;

MySQL 语法:

SELECT column_name(s)
FROM table_name
WHERE condition
LIMIT number;

Oracle 语法:

SELECT column_name(s)
FROM table_name
WHERE ROWNUM <= number;

演示数据库

以下是从示例数据库的 "客户(Customers)" 表中查询的内容:

CustomerID CustomerName ContactName Address City PostalCode Country
1
 
Alfreds Futterkiste Maria Anders Obere Str. 57 Berlin 12209 Germany
2 Ana Trujillo Emparedados y helados Ana Trujillo Avda. de la Constitución 2222 México D.F. 05021 Mexico
3 Antonio Moreno Taquería Antonio Moreno Mataderos 2312 México D.F. 05023 Mexico
4
 
Around the Horn Thomas Hardy 120 Hanover Sq. London WA1 1DP UK
5 Berglunds snabbköp Christina Berglund Berguvsvägen 8 Luleå S-958 22 Sweden

SQL TOP、LIMIT 和 ROWNUM 示例

以下 SQL 语句从 "Customers" 表中选择前三条记录(用于 SQL Server/MS Access):

【实例】

SELECT TOP 3 * FROM Customers;

下面的 SQL 语句显示使用 LIMIT 子句的等效示例(用于 MySQL):

【实例】

SELECT * FROM Customers
LIMIT 3;

下面的 SQL 语句显示使用 ROWNUM 子句的等效示例(用于 Oracle):

【实例】

SELECT * FROM Customers
WHERE ROWNUM <= 3;

SQL TOP PERCENT 实例

在 Microsoft SQL Server 中还可以使用百分比作为参数。

以下 SQL 语句从 "Customers" 表中选择前 50% 的记录(用于SQL Server/MS Access):

【实例】

SELECT TOP 50 PERCENT * FROM Customers;

添加WHERE子句

以下 SQL 语句从 "Customers" 表中选择前三条记录,其中 country 为 "Germany"(用于SQL Server/MS Access):

【实例】

SELECT TOP 3 * FROM Customers
WHERE Country='Germany';

下面的 SQL 语句显示了使用 LIMIT 子句的等效示例(用于 MySQL):

【实例】

SELECT * FROM Customers
WHERE Country='Germany'
LIMIT 3;

下面的 SQL 语句显示了使用 ROWNUM 子句的等效示例(用于 Oracle):

【实例】

SELECT * FROM Customers
WHERE Country='Germany' AND ROWNUM <= 3;

SQL MIN() 和 MAX() 函数

MIN() 和 MAX() 函数

MIN 函数返回一列中的最小值。NULL 值不包括在计算中。

MAX 函数返回一列中的最大值。NULL 值不包括在计算中。

【MIN() 语法】

SELECT MIN(column_name)
FROM table_name
WHERE condition;

【MAX() 语法】

SELECT MAX(column_name)
FROM table_name
WHERE condition;

演示数据库

以下是从示例数据库的 "Products" 表中选择的内容:

ProductID ProductName SupplierID CategoryID Unit Price
1 Chais 1 1 10 boxes x 20 bags 18
2 Chang 1 1 24 - 12 oz bottles 19
3 Aniseed Syrup 1 2 12 - 550 ml bottles 10
4 Chef Anton's Cajun Seasoning 2 2 48 - 6 oz jars 22
5 Chef Anton's Gumbo Mix 2 2 36 boxes 21.35

MIN() 实例

以下 SQL 语句查找最便宜产品的价格:

【实例】

SELECT MIN(Price) AS SmallestPrice
FROM Products;

MAX() 实例

以下 SQL 语句查找最昂贵产品的价格:

【实例】

SELECT MAX(Price) AS LargestPrice
FROM Products;

SQL COUNT(), AVG() 和 SUM() 函数

COUNT(), AVG() 和 SUM() 函数

COUNT() 函数返回匹配指定条件的行数。

AVG 函数返回数值列的平均值。NULL 值不包括在计算中。

SUM 函数返回数值列的总数(总额)。

【COUNT() 语法】

SELECT COUNT(column_name)
FROM table_name
WHERE condition;

【AVG() 语法】

SELECT AVG(column_name)
FROM table_name
WHERE condition;

【SUM() 语法】

SELECT SUM(column_name)
FROM table_name
WHERE condition;

演示数据库

以下是从示例数据库的 "Products" 表中选择的内容:

ProductID ProductName SupplierID CategoryID Unit Price
1 Chais 1 1 10 boxes x 20 bags 18
2 Chang 1 1 24 - 12 oz bottles 19
3 Aniseed Syrup 1 2 12 - 550 ml bottles 10
4 Chef Anton's Cajun Seasoning 2 2 48 - 6 oz jars 22
5 Chef Anton's Gumbo Mix 2 2 36 boxes 21.35

COUNT() 实例

以下 SQL 语句查找产品的数量:

【实例】

SELECT COUNT(ProductID)
FROM Products;

注: 不计算 NULL 空值。

AVG() 实例

以下 SQL 语句查找所有产品的平均价格:

【实例】

SELECT AVG(Price)
FROM Products;

注: 忽略 NULL 空值。

演示数据库

以下是从示例数据库的 "OrderDetails" 表中选择的内容:

OrderDetailID OrderID ProductID Quantity
1 10248 11 12
2 10248 42 10
3 10248 72 5
4 10249 14 9
5 10249 51 40

SUM() 实例

以下 SQL 语句查找 "OrderDetails" 表中 "Quantity" 字段的总和:

【实例】

SELECT SUM(Quantity)
FROM OrderDetails;

注: 忽略 NULL 空值。

SQL LIKE 操作符

SQL LIKE 操作符

LIKE 操作符在 WHERE 子句中用于搜索列中的指定模式。

有两个通配符经常与 LIKE 操作符一起使用:

  • % - 百分号表示零个、一个或多个字符
  • _ - 下划线表示单个字符

注: MS Access使用星号 (*) 代替百分号 (%),使用问号 (?) 代替下划线 (_)。百分号和下划线也可以组合使用!

【LIKE 语法】

SELECT column1, column2, ...
FROM table_name
WHERE columnN LIKE pattern;

注: 还可以使用 AND 或 OR 运算符组合任意数量的条件。

以下是一些示例,显示了使用'%' 和 '_'通配符的不同 LIKE 运算符:

LIKE Operator 描述
WHERE CustomerName LIKE 'a%' Finds any values that start with "a"
WHERE CustomerName LIKE '%a' Finds any values that end with "a"
WHERE CustomerName LIKE '%or%' Finds any values that have "or" in any position
WHERE CustomerName LIKE '_r%' Finds any values that have "r" in the second position
WHERE CustomerName LIKE 'a_%' Finds any values that start with "a" and are at least 2 characters in length
WHERE CustomerName LIKE 'a__%' Finds any values that start with "a" and are at least 3 characters in length
WHERE ContactName LIKE 'a%o' Finds any values that start with "a" and ends with "o"

演示数据库

下表显示了样本数据库中完整的客户(Customers) 表:

CustomerID CustomerName ContactName Address City PostalCode Country
1 Alfreds Futterkiste Maria Anders Obere Str. 57 Berlin 12209 Germany
2 Ana Trujillo Emparedados y helados Ana Trujillo Avda. de la Constitución 2222 México D.F. 05021 Mexico
3 Antonio Moreno Taquería Antonio Moreno Mataderos 2312 México D.F. 05023 Mexico
4 Around the Horn Thomas Hardy 120 Hanover Sq. London WA1 1DP UK
5 Berglunds snabbköp Christina Berglund Berguvsvägen 8 Luleå S-958 22 Sweden
6 Blauer See Delikatessen Hanna Moos Forsterstr. 57 Mannheim 68306 Germany
7 Blondel père et fils Frédérique Citeaux 24, place Kléber Strasbourg 67000 France
8 Bólido Comidas preparadas Martín Sommer C/ Araquil, 67 Madrid 28023 Spain
9 Bon app' Laurence Lebihans 12, rue des Bouchers Marseille 13008 France
10 Bottom-Dollar Marketse Elizabeth Lincoln 23 Tsawassen Blvd. Tsawassen T2F 8M4 Canada
11 B's Beverages Victoria Ashworth Fauntleroy Circus London EC2 5NT UK
12 Cactus Comidas para llevar Patricio Simpson Cerrito 333 Buenos Aires 1010 Argentina
13 Centro comercial Moctezuma Francisco Chang Sierras de Granada 9993 México D.F. 05022 Mexico
14 Chop-suey Chinese Yang Wang Hauptstr. 29 Bern 3012 Switzerland
15 Comércio Mineiro Pedro Afonso Av. dos Lusíadas, 23 São Paulo 05432-043 Brazil
16 Consolidated Holdings Elizabeth Brown Berkeley Gardens 12 Brewery London WX1 6LT UK
17 Drachenblut Delikatessend Sven Ottlieb Walserweg 21 Aachen 52066 Germany
18 Du monde entier Janine Labrune 67, rue des Cinquante Otages Nantes 44000 France
19 Eastern Connection Ann Devon 35 King George London WX3 6FW UK
20 Ernst Handel Roland Mendel Kirchgasse 6 Graz 8010 Austria
21 Familia Arquibaldo Aria Cruz Rua Orós, 92 São Paulo 05442-030 Brazil
22 FISSA Fabrica Inter. Salchichas S.A. Diego Roel C/ Moralzarzal, 86 Madrid 28034 Spain
23 Folies gourmandes Martine Rancé 184, chaussée de Tournai Lille 59000 France
24 Folk och fä HB Maria Larsson Åkergatan 24 Bräcke S-844 67 Sweden
25 Frankenversand Peter Franken Berliner Platz 43 München 80805 Germany
26 France restauration Carine Schmitt 54, rue Royale Nantes 44000 France
27 Franchi S.p.A. Paolo Accorti Via Monte Bianco 34 Torino 10100 Italy
28 Furia Bacalhau e Frutos do Mar Lino Rodriguez Jardim das rosas n. 32 Lisboa 1675 Portugal
29 Galería del gastrónomo Eduardo Saavedra Rambla de Cataluña, 23 Barcelona 08022 Spain
30 Godos Cocina Típica José Pedro Freyre C/ Romero, 33 Sevilla 41101 Spain
31 Gourmet Lanchonetes André Fonseca Av. Brasil, 442 Campinas 04876-786 Brazil
32 Great Lakes Food Market Howard Snyder 2732 Baker Blvd. Eugene 97403 USA
33 GROSELLA-Restaurante Manuel Pereira 5ª Ave. Los Palos Grandes Caracas 1081 Venezuela
34 Hanari Carnes Mario Pontes Rua do Paço, 67 Rio de Janeiro 05454-876 Brazil
35 HILARIÓN-Abastos Carlos Hernández Carrera 22 con Ave. Carlos Soublette #8-35 San Cristóbal 5022 Venezuela
36 Hungry Coyote Import Store Yoshi Latimer City Center Plaza 516 Main St. Elgin 97827 USA
37 Hungry Owl All-Night Grocers Patricia McKenna 8 Johnstown Road Cork Ireland
38 Island Trading Helen Bennett Garden House Crowther Way Cowes PO31 7PJ UK
39 Königlich Essen Philip Cramer Maubelstr. 90 Brandenburg 14776 Germany
40 La corne d'abondance Daniel Tonini 67, avenue de l'Europe Versailles 78000 France
41 La maison d'Asie Annette Roulet 1 rue Alsace-Lorraine Toulouse 31000 France
42 Laughing Bacchus Wine Cellars Yoshi Tannamuri 1900 Oak St. Vancouver V3F 2K1 Canada
43 Lazy K Kountry Store John Steel 12 Orchestra Terrace Walla Walla 99362 USA
44 Lehmanns Marktstand Renate Messner Magazinweg 7 Frankfurt a.M. 60528 Germany
45 Let's Stop N Shop Jaime Yorres 87 Polk St. Suite 5 San Francisco 94117 USA
46 LILA-Supermercado Carlos González Carrera 52 con Ave. Bolívar #65-98 Llano Largo Barquisimeto 3508 Venezuela
47 LINO-Delicateses Felipe Izquierdo Ave. 5 de Mayo Porlamar I. de Margarita 4980 Venezuela
48 Lonesome Pine Restaurant Fran Wilson 89 Chiaroscuro Rd. Portland 97219 USA
49 Magazzini Alimentari Riuniti Giovanni Rovelli Via Ludovico il Moro 22 Bergamo 24100 Italy
50 Maison Dewey Catherine Dewey Rue Joseph-Bens 532 Bruxelles B-1180 Belgium
51 Mère Paillarde Jean Fresnière 43 rue St. Laurent Montréal H1J 1C3 Canada
52 Morgenstern Gesundkost Alexander Feuer Heerstr. 22 Leipzig 04179 Germany
53 North/South Simon Crowther South House 300 Queensbridge London SW7 1RZ UK
54 Océano Atlántico Ltda. Yvonne Moncada Ing. Gustavo Moncada 8585 Piso 20-A Buenos Aires 1010 Argentina
55 Old World Delicatessen Rene Phillips 2743 Bering St. Anchorage 99508 USA
56 Ottilies Käseladen Henriette Pfalzheim Mehrheimerstr. 369 Köln 50739 Germany
57 Paris spécialités Marie Bertrand 265, boulevard Charonne Paris 75012 France
58 Pericles Comidas clásicas Guillermo Fernández Calle Dr. Jorge Cash 321 México D.F. 05033 Mexico
59 Piccolo und mehr Georg Pipps Geislweg 14 Salzburg 5020 Austria
60 Princesa Isabel Vinhoss Isabel de Castro Estrada da saúde n. 58 Lisboa 1756 Portugal
61 Que Delícia Bernardo Batista Rua da Panificadora, 12 Rio de Janeiro 02389-673 Brazil
62 Queen Cozinha Lúcia Carvalho Alameda dos Canàrios, 891 São Paulo 05487-020 Brazil
63 QUICK-Stop Horst Kloss Taucherstraße 10 Cunewalde 01307 Germany
64 Rancho grande Sergio Gutiérrez Av. del Libertador 900 Buenos Aires 1010 Argentina
65 Rattlesnake Canyon Grocery Paula Wilson 2817 Milton Dr. Albuquerque 87110 USA
66 Reggiani Caseifici Maurizio Moroni Strada Provinciale 124 Reggio Emilia 42100 Italy
67 Ricardo Adocicados Janete Limeira Av. Copacabana, 267 Rio de Janeiro 02389-890 Brazil
68 Richter Supermarkt Michael Holz Grenzacherweg 237 Genève 1203 Switzerland
69 Romero y tomillo Alejandra Camino Gran Vía, 1 Madrid 28001 Spain
70 Santé Gourmet Jonas Bergulfsen Erling Skakkes gate 78 Stavern 4110 Norway
71 Save-a-lot Markets Jose Pavarotti 187 Suffolk Ln. Boise 83720 USA
72 Seven Seas Imports Hari Kumar 90 Wadhurst Rd. London OX15 4NB UK
73 Simons bistro Jytte Petersen Vinbæltet 34 København 1734 Denmark
74 Spécialités du monde Dominique Perrier 25, rue Lauriston Paris 75016 France
75 Split Rail Beer & Ale Art Braunschweiger P.O. Box 555 Lander 82520 USA
76 Suprêmes délices Pascale Cartrain Boulevard Tirou, 255 Charleroi B-6000 Belgium
77 The Big Cheese Liz Nixon 89 Jefferson Way Suite 2 Portland 97201 USA
78 The Cracker Box Liu Wong 55 Grizzly Peak Rd. Butte 59801 USA
79 Toms Spezialitäten Karin Josephs Luisenstr. 48 Münster 44087 Germany
80 Tortuga Restaurante Miguel Angel Paolino Avda. Azteca 123 México D.F. 05033 Mexico
81 Tradição Hipermercados Anabela Domingues Av. Inês de Castro, 414 São Paulo 05634-030 Brazil
82 Trail's Head Gourmet Provisioners Helvetius Nagy 722 DaVinci Blvd. Kirkland 98034 USA
83 Vaffeljernet Palle Ibsen Smagsløget 45 Århus 8200 Denmark
84 Victuailles en stock Mary Saveley 2, rue du Commerce Lyon 69004 France
85 Vins et alcools Chevalier Paul Henriot 59 rue de l'Abbaye Reims 51100 France
86 Die Wandernde Kuh Rita Müller Adenauerallee 900 Stuttgart 70563 Germany
87 Wartian Herkku Pirkko Koskitalo Torikatu 38 Oulu 90110 Finland
88 Wellington Importadora Paula Parente Rua do Mercado, 12 Resende 08737-363 Brazil
89 White Clover Markets Karl Jablonski 305 - 14th Ave. S. Suite 3B Seattle 98128 USA
90 Wilman Kala Matti Karttunen Keskuskatu 45 Helsinki 21240 Finland
91 Wolski Zbyszek ul. Filtrowa 68 Walla 01-012 Poland

LIKE 操作符实例

以下 SQL 语句选择 CustomerName 以 "a" 开头的所有客户:

【实例】

SELECT * FROM Customers
WHERE CustomerName LIKE 'a%';

以下 SQL 语句选择 CustomerName 以 "a" 结尾的所有客户:

【实例】

SELECT * FROM Customers
WHERE CustomerName LIKE '%a';

下面的 SQL 语句选择 CustomerName 中任何位置都有 "or" 的所有客户:

【实例】

SELECT * FROM Customers
WHERE CustomerName LIKE '%or%';

下面的 SQL 语句选择 CustomerName 第二个位置有 "r" 的所有客户:

【实例】

SELECT * FROM Customers
WHERE CustomerName LIKE '_r%';

以下 SQL 语句选择 CustomerName 以 "a" 开头且长度至少为3个字符的所有客户:

【实例】

SELECT * FROM Customers
WHERE CustomerName LIKE 'a__%';

以下 SQL 语句选择 ContactName 以 "a" 开头、以 "o" 结尾的所有客户:

【实例】

SELECT * FROM Customers
WHERE ContactName LIKE 'a%o';

以下 SQL 语句选择 CustomerName 不以 "a" 开头的所有客户:

【实例】

SELECT * FROM Customers
WHERE CustomerName NOT LIKE 'a%';

SQL 通配符

SQL 通配符

通配符可用于替代字符串中的任何其他字符。


通配符与 SQL LIKE 运算符一起使用。LIKE 运算符在 WHERE 子句中用于搜索列中的指定模式。

【MS Access中的通配符】

Symbol 描述 例子
* 代表零个或多个字符 bl* finds bl, black, blue, and blob
? 代表单个字符 h?t finds hot, hat, and hit
[] 表示括号内的任意单个字符 h[oa]t finds hot and hat, but not hit
! 代表任何不在括号内的字符 h[!oa]t finds hit, but not hot and hat
- 代表一系列字符 c[a-b]t finds cat and cbt
# 表示任意单个数字字符 2#5 finds 205, 215, 225, 235, 245, 255, 265, 275, 285, and 295

【SQL Server 中的通配符】

Symbol 描述 例子
% 代表零个或多个字符 bl% finds bl, black, blue, and blob
_ 代表单个字符 h_t finds hot, hat, and hit
[] 表示括号内的任意单个字符 h[oa]t finds hot and hat, but not hit
^ 代表任何不在括号内的字符 h[^oa]t finds hit, but not hot and hat
- 代表一系列字符 c[a-b]t finds cat and cbt

所有通配符也可以组合使用!

以下是一些示例,显示了 LIKE 运算符使用 '%' 和 '_' 通配符的不同:

LIKE 操作符 描述
WHERE CustomerName LIKE 'a%' Finds any values that starts with "a"
WHERE CustomerName LIKE '%a' Finds any values that ends with "a"
WHERE CustomerName LIKE '%or%' Finds any values that have "or" in any position
WHERE CustomerName LIKE '_r%' Finds any values that have "r" in the second position
WHERE CustomerName LIKE 'a_%_%' Finds any values that starts with "a" and are at least 3 characters in length
WHERE ContactName LIKE 'a%o' Finds any values that starts with "a" and ends with "o"

演示数据库

下表显示了样本数据库中完整的客户(Customers) 表:

CustomerID CustomerName ContactName Address City PostalCode Country
1 Alfreds Futterkiste Maria Anders Obere Str. 57 Berlin 12209 Germany
2 Ana Trujillo Emparedados y helados Ana Trujillo Avda. de la Constitución 2222 México D.F. 05021 Mexico
3 Antonio Moreno Taquería Antonio Moreno Mataderos 2312 México D.F. 05023 Mexico
4 Around the Horn Thomas Hardy 120 Hanover Sq. London WA1 1DP UK
5 Berglunds snabbköp Christina Berglund Berguvsvägen 8 Luleå S-958 22 Sweden
6 Blauer See Delikatessen Hanna Moos Forsterstr. 57 Mannheim 68306 Germany
7 Blondel père et fils Frédérique Citeaux 24, place Kléber Strasbourg 67000 France
8 Bólido Comidas preparadas Martín Sommer C/ Araquil, 67 Madrid 28023 Spain
9 Bon app' Laurence Lebihans 12, rue des Bouchers Marseille 13008 France
10 Bottom-Dollar Marketse Elizabeth Lincoln 23 Tsawassen Blvd. Tsawassen T2F 8M4 Canada
11 B's Beverages Victoria Ashworth Fauntleroy Circus London EC2 5NT UK
12 Cactus Comidas para llevar Patricio Simpson Cerrito 333 Buenos Aires 1010 Argentina
13 Centro comercial Moctezuma Francisco Chang Sierras de Granada 9993 México D.F. 05022 Mexico
14 Chop-suey Chinese Yang Wang Hauptstr. 29 Bern 3012 Switzerland
15 Comércio Mineiro Pedro Afonso Av. dos Lusíadas, 23 São Paulo 05432-043 Brazil
16 Consolidated Holdings Elizabeth Brown Berkeley Gardens 12 Brewery London WX1 6LT UK
17 Drachenblut Delikatessend Sven Ottlieb Walserweg 21 Aachen 52066 Germany
18 Du monde entier Janine Labrune 67, rue des Cinquante Otages Nantes 44000 France
19 Eastern Connection Ann Devon 35 King George London WX3 6FW UK
20 Ernst Handel Roland Mendel Kirchgasse 6 Graz 8010 Austria
21 Familia Arquibaldo Aria Cruz Rua Orós, 92 São Paulo 05442-030 Brazil
22 FISSA Fabrica Inter. Salchichas S.A. Diego Roel C/ Moralzarzal, 86 Madrid 28034 Spain
23 Folies gourmandes Martine Rancé 184, chaussée de Tournai Lille 59000 France
24 Folk och fä HB Maria Larsson Åkergatan 24 Bräcke S-844 67 Sweden
25 Frankenversand Peter Franken Berliner Platz 43 München 80805 Germany
26 France restauration Carine Schmitt 54, rue Royale Nantes 44000 France
27 Franchi S.p.A. Paolo Accorti Via Monte Bianco 34 Torino 10100 Italy
28 Furia Bacalhau e Frutos do Mar Lino Rodriguez Jardim das rosas n. 32 Lisboa 1675 Portugal
29 Galería del gastrónomo Eduardo Saavedra Rambla de Cataluña, 23 Barcelona 08022 Spain
30 Godos Cocina Típica José Pedro Freyre C/ Romero, 33 Sevilla 41101 Spain
31 Gourmet Lanchonetes André Fonseca Av. Brasil, 442 Campinas 04876-786 Brazil
32 Great Lakes Food Market Howard Snyder 2732 Baker Blvd. Eugene 97403 USA
33 GROSELLA-Restaurante Manuel Pereira 5ª Ave. Los Palos Grandes Caracas 1081 Venezuela
34 Hanari Carnes Mario Pontes Rua do Paço, 67 Rio de Janeiro 05454-876 Brazil
35 HILARIÓN-Abastos Carlos Hernández Carrera 22 con Ave. Carlos Soublette #8-35 San Cristóbal 5022 Venezuela
36 Hungry Coyote Import Store Yoshi Latimer City Center Plaza 516 Main St. Elgin 97827 USA
37 Hungry Owl All-Night Grocers Patricia McKenna 8 Johnstown Road Cork Ireland
38 Island Trading Helen Bennett Garden House Crowther Way Cowes PO31 7PJ UK
39 Königlich Essen Philip Cramer Maubelstr. 90 Brandenburg 14776 Germany
40 La corne d'abondance Daniel Tonini 67, avenue de l'Europe Versailles 78000 France
41 La maison d'Asie Annette Roulet 1 rue Alsace-Lorraine Toulouse 31000 France
42 Laughing Bacchus Wine Cellars Yoshi Tannamuri 1900 Oak St. Vancouver V3F 2K1 Canada
43 Lazy K Kountry Store John Steel 12 Orchestra Terrace Walla Walla 99362 USA
44 Lehmanns Marktstand Renate Messner Magazinweg 7 Frankfurt a.M. 60528 Germany
45 Let's Stop N Shop Jaime Yorres 87 Polk St. Suite 5 San Francisco 94117 USA
46 LILA-Supermercado Carlos González Carrera 52 con Ave. Bolívar #65-98 Llano Largo Barquisimeto 3508 Venezuela
47 LINO-Delicateses Felipe Izquierdo Ave. 5 de Mayo Porlamar I. de Margarita 4980 Venezuela
48 Lonesome Pine Restaurant Fran Wilson 89 Chiaroscuro Rd. Portland 97219 USA
49 Magazzini Alimentari Riuniti Giovanni Rovelli Via Ludovico il Moro 22 Bergamo 24100 Italy
50 Maison Dewey Catherine Dewey Rue Joseph-Bens 532 Bruxelles B-1180 Belgium
51 Mère Paillarde Jean Fresnière 43 rue St. Laurent Montréal H1J 1C3 Canada
52 Morgenstern Gesundkost Alexander Feuer Heerstr. 22 Leipzig 04179 Germany
53 North/South Simon Crowther South House 300 Queensbridge London SW7 1RZ UK
54 Océano Atlántico Ltda. Yvonne Moncada Ing. Gustavo Moncada 8585 Piso 20-A Buenos Aires 1010 Argentina
55 Old World Delicatessen Rene Phillips 2743 Bering St. Anchorage 99508 USA
56 Ottilies Käseladen Henriette Pfalzheim Mehrheimerstr. 369 Köln 50739 Germany
57 Paris spécialités Marie Bertrand 265, boulevard Charonne Paris 75012 France
58 Pericles Comidas clásicas Guillermo Fernández Calle Dr. Jorge Cash 321 México D.F. 05033 Mexico
59 Piccolo und mehr Georg Pipps Geislweg 14 Salzburg 5020 Austria
60 Princesa Isabel Vinhoss Isabel de Castro Estrada da saúde n. 58 Lisboa 1756 Portugal
61 Que Delícia Bernardo Batista Rua da Panificadora, 12 Rio de Janeiro 02389-673 Brazil
62 Queen Cozinha Lúcia Carvalho Alameda dos Canàrios, 891 São Paulo 05487-020 Brazil
63 QUICK-Stop Horst Kloss Taucherstraße 10 Cunewalde 01307 Germany
64 Rancho grande Sergio Gutiérrez Av. del Libertador 900 Buenos Aires 1010 Argentina
65 Rattlesnake Canyon Grocery Paula Wilson 2817 Milton Dr. Albuquerque 87110 USA
66 Reggiani Caseifici Maurizio Moroni Strada Provinciale 124 Reggio Emilia 42100 Italy
67 Ricardo Adocicados Janete Limeira Av. Copacabana, 267 Rio de Janeiro 02389-890 Brazil
68 Richter Supermarkt Michael Holz Grenzacherweg 237 Genève 1203 Switzerland
69 Romero y tomillo Alejandra Camino Gran Vía, 1 Madrid 28001 Spain
70 Santé Gourmet Jonas Bergulfsen Erling Skakkes gate 78 Stavern 4110 Norway
71 Save-a-lot Markets Jose Pavarotti 187 Suffolk Ln. Boise 83720 USA
72 Seven Seas Imports Hari Kumar 90 Wadhurst Rd. London OX15 4NB UK
73 Simons bistro Jytte Petersen Vinbæltet 34 København 1734 Denmark
74 Spécialités du monde Dominique Perrier 25, rue Lauriston Paris 75016 France
75 Split Rail Beer & Ale Art Braunschweiger P.O. Box 555 Lander 82520 USA
76 Suprêmes délices Pascale Cartrain Boulevard Tirou, 255 Charleroi B-6000 Belgium
77 The Big Cheese Liz Nixon 89 Jefferson Way Suite 2 Portland 97201 USA
78 The Cracker Box Liu Wong 55 Grizzly Peak Rd. Butte 59801 USA
79 Toms Spezialitäten Karin Josephs Luisenstr. 48 Münster 44087 Germany
80 Tortuga Restaurante Miguel Angel Paolino Avda. Azteca 123 México D.F. 05033 Mexico
81 Tradição Hipermercados Anabela Domingues Av. Inês de Castro, 414 São Paulo 05634-030 Brazil
82 Trail's Head Gourmet Provisioners Helvetius Nagy 722 DaVinci Blvd. Kirkland 98034 USA
83 Vaffeljernet Palle Ibsen Smagsløget 45 Århus 8200 Denmark
84 Victuailles en stock Mary Saveley 2, rue du Commerce Lyon 69004 France
85 Vins et alcools Chevalier Paul Henriot 59 rue de l'Abbaye Reims 51100 France
86 Die Wandernde Kuh Rita Müller Adenauerallee 900 Stuttgart 70563 Germany
87 Wartian Herkku Pirkko Koskitalo Torikatu 38 Oulu 90110 Finland
88 Wellington Importadora Paula Parente Rua do Mercado, 12 Resende 08737-363 Brazil
89 White Clover Markets Karl Jablonski 305 - 14th Ave. S. Suite 3B Seattle 98128 USA
90 Wilman Kala Matti Karttunen Keskuskatu 45 Helsinki 21240 Finland
91 Wolski Zbyszek ul. Filtrowa 68 Walla 01-012 Poland

使用 % 通配符

以下SQL语句选择城市以 "ber" 开头的所有客户:

【实例】

SELECT * FROM Customers
WHERE City LIKE 'ber%';

以下 SQL 语句选择城市中包含模式 "es" 的所有客户:

【实例】

SELECT * FROM Customers
WHERE City LIKE '%es%';

使用 _ 通配符

以下 SQL 语句选择城市以任意字符开头,后跟 "ondon" 的所有客户:

【实例】

SELECT * FROM Customers
WHERE City LIKE '_ondon';

以下 SQL 语句选择城市以"L"开头、后跟任意字符、后跟"n"、后跟任意字符、后跟"on"的所有客户:

【实例】

SELECT * FROM Customers
WHERE City LIKE 'L_n_on';

使用 [charlist] 通配符

以下 SQL 语句选择城市以"b"、"s"或"p"开头的所有客户:

【实例】

SELECT * FROM Customers
WHERE City LIKE '[bsp]%';

以下 SQL 语句选择城市以"a"、"b"或"c"开头的所有客户:

【实例】

SELECT * FROM Customers
WHERE City LIKE '[a-c]%';

使用 [!charlist] 通配符

以下两条SQL语句选择城市不以"b"、"s"或"p"开头的所有客户:

【实例】

SELECT * FROM Customers
WHERE City LIKE '[!bsp]%';

或者:

【实例】

SELECT * FROM Customers
WHERE City NOT LIKE '[bsp]%';

SQL IN 操作符

SQL IN 操作符

IN 操作符允许我们在 WHERE 子句中规定多个值。

IN 操作符是多个OR条件的简写。

【IN 语法】

SELECT column_name(s)
FROM table_name
WHERE column_name IN (value1, value2, ...);

或者:

SELECT column_name(s)
FROM table_name
WHERE column_name IN (SELECT STATEMENT);

演示数据库

下表显示了样本数据库中完整的客户(Customers) 表:

CustomerID CustomerName ContactName Address City PostalCode Country
1 Alfreds Futterkiste Maria Anders Obere Str. 57 Berlin 12209 Germany
2 Ana Trujillo Emparedados y helados Ana Trujillo Avda. de la Constitución 2222 México D.F. 05021 Mexico
3 Antonio Moreno Taquería Antonio Moreno Mataderos 2312 México D.F. 05023 Mexico
4 Around the Horn Thomas Hardy 120 Hanover Sq. London WA1 1DP UK
5 Berglunds snabbköp Christina Berglund Berguvsvägen 8 Luleå S-958 22 Sweden
6 Blauer See Delikatessen Hanna Moos Forsterstr. 57 Mannheim 68306 Germany
7 Blondel père et fils Frédérique Citeaux 24, place Kléber Strasbourg 67000 France
8 Bólido Comidas preparadas Martín Sommer C/ Araquil, 67 Madrid 28023 Spain
9 Bon app' Laurence Lebihans 12, rue des Bouchers Marseille 13008 France
10 Bottom-Dollar Marketse Elizabeth Lincoln 23 Tsawassen Blvd. Tsawassen T2F 8M4 Canada
11 B's Beverages Victoria Ashworth Fauntleroy Circus London EC2 5NT UK
12 Cactus Comidas para llevar Patricio Simpson Cerrito 333 Buenos Aires 1010 Argentina
13 Centro comercial Moctezuma Francisco Chang Sierras de Granada 9993 México D.F. 05022 Mexico
14 Chop-suey Chinese Yang Wang Hauptstr. 29 Bern 3012 Switzerland
15 Comércio Mineiro Pedro Afonso Av. dos Lusíadas, 23 São Paulo 05432-043 Brazil
16 Consolidated Holdings Elizabeth Brown Berkeley Gardens 12 Brewery London WX1 6LT UK
17 Drachenblut Delikatessend Sven Ottlieb Walserweg 21 Aachen 52066 Germany
18 Du monde entier Janine Labrune 67, rue des Cinquante Otages Nantes 44000 France
19 Eastern Connection Ann Devon 35 King George London WX3 6FW UK
20 Ernst Handel Roland Mendel Kirchgasse 6 Graz 8010 Austria
21 Familia Arquibaldo Aria Cruz Rua Orós, 92 São Paulo 05442-030 Brazil
22 FISSA Fabrica Inter. Salchichas S.A. Diego Roel C/ Moralzarzal, 86 Madrid 28034 Spain
23 Folies gourmandes Martine Rancé 184, chaussée de Tournai Lille 59000 France
24 Folk och fä HB Maria Larsson Åkergatan 24 Bräcke S-844 67 Sweden
25 Frankenversand Peter Franken Berliner Platz 43 München 80805 Germany
26 France restauration Carine Schmitt 54, rue Royale Nantes 44000 France
27 Franchi S.p.A. Paolo Accorti Via Monte Bianco 34 Torino 10100 Italy
28 Furia Bacalhau e Frutos do Mar Lino Rodriguez Jardim das rosas n. 32 Lisboa 1675 Portugal
29 Galería del gastrónomo Eduardo Saavedra Rambla de Cataluña, 23 Barcelona 08022 Spain
30 Godos Cocina Típica José Pedro Freyre C/ Romero, 33 Sevilla 41101 Spain
31 Gourmet Lanchonetes André Fonseca Av. Brasil, 442 Campinas 04876-786 Brazil
32 Great Lakes Food Market Howard Snyder 2732 Baker Blvd. Eugene 97403 USA
33 GROSELLA-Restaurante Manuel Pereira 5ª Ave. Los Palos Grandes Caracas 1081 Venezuela
34 Hanari Carnes Mario Pontes Rua do Paço, 67 Rio de Janeiro 05454-876 Brazil
35 HILARIÓN-Abastos Carlos Hernández Carrera 22 con Ave. Carlos Soublette #8-35 San Cristóbal 5022 Venezuela
36 Hungry Coyote Import Store Yoshi Latimer City Center Plaza 516 Main St. Elgin 97827 USA
37 Hungry Owl All-Night Grocers Patricia McKenna 8 Johnstown Road Cork Ireland
38 Island Trading Helen Bennett Garden House Crowther Way Cowes PO31 7PJ UK
39 Königlich Essen Philip Cramer Maubelstr. 90 Brandenburg 14776 Germany
40 La corne d'abondance Daniel Tonini 67, avenue de l'Europe Versailles 78000 France
41 La maison d'Asie Annette Roulet 1 rue Alsace-Lorraine Toulouse 31000 France
42 Laughing Bacchus Wine Cellars Yoshi Tannamuri 1900 Oak St. Vancouver V3F 2K1 Canada
43 Lazy K Kountry Store John Steel 12 Orchestra Terrace Walla Walla 99362 USA
44 Lehmanns Marktstand Renate Messner Magazinweg 7 Frankfurt a.M. 60528 Germany
45 Let's Stop N Shop Jaime Yorres 87 Polk St. Suite 5 San Francisco 94117 USA
46 LILA-Supermercado Carlos González Carrera 52 con Ave. Bolívar #65-98 Llano Largo Barquisimeto 3508 Venezuela
47 LINO-Delicateses Felipe Izquierdo Ave. 5 de Mayo Porlamar I. de Margarita 4980 Venezuela
48 Lonesome Pine Restaurant Fran Wilson 89 Chiaroscuro Rd. Portland 97219 USA
49 Magazzini Alimentari Riuniti Giovanni Rovelli Via Ludovico il Moro 22 Bergamo 24100 Italy
50 Maison Dewey Catherine Dewey Rue Joseph-Bens 532 Bruxelles B-1180 Belgium
51 Mère Paillarde Jean Fresnière 43 rue St. Laurent Montréal H1J 1C3 Canada
52 Morgenstern Gesundkost Alexander Feuer Heerstr. 22 Leipzig 04179 Germany
53 North/South Simon Crowther South House 300 Queensbridge London SW7 1RZ UK
54 Océano Atlántico Ltda. Yvonne Moncada Ing. Gustavo Moncada 8585 Piso 20-A Buenos Aires 1010 Argentina
55 Old World Delicatessen Rene Phillips 2743 Bering St. Anchorage 99508 USA
56 Ottilies Käseladen Henriette Pfalzheim Mehrheimerstr. 369 Köln 50739 Germany
57 Paris spécialités Marie Bertrand 265, boulevard Charonne Paris 75012 France
58 Pericles Comidas clásicas Guillermo Fernández Calle Dr. Jorge Cash 321 México D.F. 05033 Mexico
59 Piccolo und mehr Georg Pipps Geislweg 14 Salzburg 5020 Austria
60 Princesa Isabel Vinhoss Isabel de Castro Estrada da saúde n. 58 Lisboa 1756 Portugal
61 Que Delícia Bernardo Batista Rua da Panificadora, 12 Rio de Janeiro 02389-673 Brazil
62 Queen Cozinha Lúcia Carvalho Alameda dos Canàrios, 891 São Paulo 05487-020 Brazil
63 QUICK-Stop Horst Kloss Taucherstraße 10 Cunewalde 01307 Germany
64 Rancho grande Sergio Gutiérrez Av. del Libertador 900 Buenos Aires 1010 Argentina
65 Rattlesnake Canyon Grocery Paula Wilson 2817 Milton Dr. Albuquerque 87110 USA
66 Reggiani Caseifici Maurizio Moroni Strada Provinciale 124 Reggio Emilia 42100 Italy
67 Ricardo Adocicados Janete Limeira Av. Copacabana, 267 Rio de Janeiro 02389-890 Brazil
68 Richter Supermarkt Michael Holz Grenzacherweg 237 Genève 1203 Switzerland
69 Romero y tomillo Alejandra Camino Gran Vía, 1 Madrid 28001 Spain
70 Santé Gourmet Jonas Bergulfsen Erling Skakkes gate 78 Stavern 4110 Norway
71 Save-a-lot Markets Jose Pavarotti 187 Suffolk Ln. Boise 83720 USA
72 Seven Seas Imports Hari Kumar 90 Wadhurst Rd. London OX15 4NB UK
73 Simons bistro Jytte Petersen Vinbæltet 34 København 1734 Denmark
74 Spécialités du monde Dominique Perrier 25, rue Lauriston Paris 75016 France
75 Split Rail Beer & Ale Art Braunschweiger P.O. Box 555 Lander 82520 USA
76 Suprêmes délices Pascale Cartrain Boulevard Tirou, 255 Charleroi B-6000 Belgium
77 The Big Cheese Liz Nixon 89 Jefferson Way Suite 2 Portland 97201 USA
78 The Cracker Box Liu Wong 55 Grizzly Peak Rd. Butte 59801 USA
79 Toms Spezialitäten Karin Josephs Luisenstr. 48 Münster 44087 Germany
80 Tortuga Restaurante Miguel Angel Paolino Avda. Azteca 123 México D.F. 05033 Mexico
81 Tradição Hipermercados Anabela Domingues Av. Inês de Castro, 414 São Paulo 05634-030 Brazil
82 Trail's Head Gourmet Provisioners Helvetius Nagy 722 DaVinci Blvd. Kirkland 98034 USA
83 Vaffeljernet Palle Ibsen Smagsløget 45 Århus 8200 Denmark
84 Victuailles en stock Mary Saveley 2, rue du Commerce Lyon 69004 France
85 Vins et alcools Chevalier Paul Henriot 59 rue de l'Abbaye Reims 51100 France
86 Die Wandernde Kuh Rita Müller Adenauerallee 900 Stuttgart 70563 Germany
87 Wartian Herkku Pirkko Koskitalo Torikatu 38 Oulu 90110 Finland
88 Wellington Importadora Paula Parente Rua do Mercado, 12 Resende 08737-363 Brazil
89 White Clover Markets Karl Jablonski 305 - 14th Ave. S. Suite 3B Seattle 98128 USA
90 Wilman Kala Matti Karttunen Keskuskatu 45 Helsinki 21240 Finland
91 Wolski Zbyszek ul. Filtrowa 68 Walla 01-012 Poland

IN 操作符实例

以下 SQL 语句选择位于 "Germany", "France", "UK" 的所有客户:

【实例】

SELECT * FROM Customers
WHERE Country IN ('Germany', 'France', 'UK');

以下 SQL 语句选择不在 "Germany", "France" or "UK" 的所有客户:

【实例】

SELECT * FROM Customers
WHERE Country NOT IN ('Germany', 'France', 'UK');

以下 SQL 语句选择与供应商来自相同国家/地区的所有客户:

【实例】

SELECT * FROM Customers
WHERE Country IN (SELECT Country FROM Suppliers);

SQL BETWEEN 操作符

SQL BETWEEN 操作符

BETWEEN 操作符在 WHERE 子句中使用,作用是选取介于两个值之间的数据范围。这些值可以是数值、文本或者日期。

BETWEEN 操作符包括开始值和结束值。

【BETWEEN 语法】

SELECT column_name(s)
FROM table_name
WHERE column_name BETWEEN value1 AND value2;

演示数据库

以下是从示例数据库的 产品(Products) 表中选择的内容:

ProductID ProductName SupplierID CategoryID Unit Price
1 Chais 1 1 10 boxes x 20 bags 18
2 Chang 1 1 24 - 12 oz bottles 19
3 Aniseed Syrup 1 2 12 - 550 ml bottles 10
4 Chef Anton's Cajun Seasoning 1 2 48 - 6 oz jars 22
5 Chef Anton's Gumbo Mix 1 2 36 boxes 21.35

BETWEEN 实例

以下 SQL 语句选择价格介于 10 和 20 之间的所有产品:

【实例】

SELECT * FROM Products
WHERE Price BETWEEN 10 AND 20;

NOT BETWEEN 实例

要显示上一示例范围之外的产品,请使用 NOT BETWEEN:

【实例】

SELECT * FROM Products
WHERE Price NOT BETWEEN 10 AND 20;

带有 IN 的 BETWEEN 操作符实例

下面的 SQL 语句选择价格介于 10 和 20 之间的所有产品。此外请勿显示 CategoryID 为1、2或3的产品:

【实例】

SELECT * FROM Products
WHERE Price BETWEEN 10 AND 20
AND CategoryID NOT IN (1,2,3);

带有文本值的 BETWEEN 操作符实例

以下 SQL 语句选择所有产品,其产品名称介于 Carnavon Tigers 和 Mozzarella di Giovanni 之间:

【实例】

SELECT * FROM Products
WHERE ProductName BETWEEN 'Carnarvon Tigers' AND 'Mozzarella di Giovanni'
ORDER BY ProductName;

以下SQL语句选择所有产品,产品名称介于 Carnarvon Tigers 和 Chef Anton's Cajun Seasoning 之间:

【实例】

SELECT * FROM Products
WHERE ProductName BETWEEN "Carnarvon Tigers" AND "Chef Anton's Cajun Seasoning"
ORDER BY ProductName;

带有文本值的 NOT BETWEEN 操作符实例

以下SQL语句选择了所有产品,其产品名称不在 Carnarvon Tigers 和 Mozzarella di Giovanni 之间:

【实例】

SELECT * FROM Products
WHERE ProductName NOT BETWEEN 'Carnarvon Tigers' AND 'Mozzarella di Giovanni'
ORDER BY ProductName;

示例表

以下是从示例数据库的 "订单(Orders)" 表中选择的内容:

OrderID CustomerID EmployeeID OrderDate ShipperID
10248 90 5 7/4/1996 3
10249 81 6 7/5/1996 1
10250 34 4 7/8/1996 2
10251 84 3 7/9/1996 1
10252 76 4 7/10/1996 2

带有日期值的 BETWEEN 操作符实例

以下 SQL 语句选择 OrderDate 介于 "1996年7月1日" 和 "1996年7月31日" 之间的所有订单:

【实例】

SELECT * FROM Orders
WHERE OrderDate BETWEEN #01/07/1996# AND #31/07/1996#;

或者:

SELECT * FROM Orders
WHERE OrderDate BETWEEN '1996-07-01' AND '1996-07-31';

SQL 别名

SQL 别名

SQL 别名用于为表或表中的列提供临时名称。

别名通常用于提高列名的可读性。

别名仅在查询期间有效。

【列的 SQL Alias 语法】

SELECT column_name AS alias_name
FROM table_name;

【表的 SQL Alias 语法】

SELECT column_name(s)
FROM table_name AS alias_name;

演示数据库

以下是从 "Customers" 表中选择的内容:

CustomerID CustomerName ContactName Address City PostalCode Country
2 Ana Trujillo Emparedados y helados Ana Trujillo Avda. de la Constitución 2222 México D.F. 05021 Mexico
3 Antonio Moreno Taquería Antonio Moreno Mataderos 2312 México D.F. 05023 Mexico
4 Around the Horn Thomas Hardy 120 Hanover Sq. London WA1 1DP UK

以及从 "Orders" 表中选择的内容:

OrderID CustomerID EmployeeID OrderDate ShipperID
10354 58 8 1996-11-14 3
10355 4 6 1996-11-15 1
10356 86 6 1996-11-18 2

Alias 实例: 使用一个列名别名

以下 SQL 语句创建两个别名,一个用于 CustomerID 列,另一个用于 CustomerName 列:

【实例】

SELECT CustomerID AS ID, CustomerName AS Customer
FROM Customers;

下面的SQL语句创建两个别名,一个用于CustomerName列,另一个用于ContactName列。

注: 如果别名包含空格,则需要双引号或方括号。

【实例】

SELECT CustomerName AS Customer, ContactName AS [Contact Person]
FROM Customers;

以下 SQL 语句创建一个名为 "Address" 的别名,该别名由四列(Address、PostalCode、City和Country)组成:

【实例】

SELECT CustomerName, Address + ', ' + PostalCode + ' ' + City + ', ' + Country AS Address
FROM Customers;

注: 要使上述 SQL 语句在 MySQL 中工作,请使用以下命令:

SELECT CustomerName, CONCAT(Address,', ',PostalCode,', ',City,', ',Country) AS Address
FROM Customers;

Alias 实例: 使用表名称别名

下面的 SQL 语句选择 CustomerID=4(Around the Horn)的客户的所有订单。我们使用 "Customers" 和 "Orders" 表,并分别为它们提供表别名 "c" 和 "o"(这里我们使用别名来缩短 SQL):

【实例】

SELECT o.OrderID, o.OrderDate, c.CustomerName
FROM Customers AS c, Orders AS o
WHERE c.CustomerName='Around the Horn' AND c.CustomerID=o.CustomerID;

以下 SQL 语句与上面相同,但没有别名:

【实例】

SELECT Orders.OrderID, Orders.OrderDate, Customers.CustomerName
FROM Customers, Orders
WHERE Customers.CustomerName='Around the Horn' AND Customers.CustomerID=Orders.CustomerID;

在下面的情况下,使用别名很有用:

  • 在查询中涉及超过一个表
  • 在查询中使用了函数
  • 列名称很长或者可读性差
  • 需要把两个列或者多个列结合在一起

SQL 联接

SQL JOIN

JOIN SQL 用于根据两个或多个表之间的一个相关列合并两个或多个表中的行。

请看 "Orders" 表:

OrderID CustomerID OrderDate
10308 2 1996-09-18
10309 37 1996-09-19
10310 77 1996-09-20

然后,请看 "Customers" 表:

CustomerID CustomerName ContactName Country
1 Alfreds Futterkiste Maria Anders Germany
2 Ana Trujillo Emparedados y helados Ana Trujillo Mexico
3 Antonio Moreno Taquería Antonio Moreno Mexico

请注意,"Customers" 表中的 "CustomerID" 列指的是 "Customers" 表中的 "CustomerID"。上面两个表之间的关系是 "CustomerID" 列。

然后,我们可以创建以下 SQL 语句(包含 INNER JOIN),用于选择两个表中具有匹配值的记录:

【实例】

SELECT Orders.OrderID, Customers.CustomerName, Orders.OrderDate
FROM Orders
INNER JOIN Customers ON Orders.CustomerID=Customers.CustomerID;

将产生如下结果:

OrderID CustomerName OrderDate
10308 Ana Trujillo Emparedados y helados 9/18/1996
10365 Antonio Moreno Taquería 11/27/1996
10383 Around the Horn 12/16/1996
10355 Around the Horn 11/15/1996
10278 Berglunds snabbköp 8/12/1996

不同类型的 SQL JOIN

下面列出了您可以使用的 JOIN 类型,以及它们之间的差异。

  • (INNER) JOIN: 如果表中有至少一个匹配,则返回行
  • LEFT (OUTER) JOIN: 即使右表中没有匹配,也从左表返回所有的行
  • RIGHT (OUTER) JOIN: 即使左表中没有匹配,也从右表返回所有的行
  • FULL (OUTER) JOIN: 只要其中一个表中存在匹配,就返回行

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