SQL MAKE_SET 函数

一、SQL MAKE_SET 函数 语法

SQL语言中的 MAKE_SET 字符串函数从多个值的集合中返回给定位的值。

在 SQL 中，我们可以对表的列、字符串和字符使用 MAKE_SET 函数。

语法1：

SELECT MAKE_SET(bits, Column_Name1, column_Name2, Column_Name3,……. Column_NameN) AS Alias_Name FROM Table_Name;  

在这种语法中，我们将 MAKE_SET 函数与现有的 SQL 表一起使用。在这里，我们必须定义要在其上执行 MAKE_SET 函数的表的名称和列。

语法2：

SELECT MAKE_SET(bits, "String1", "String2", "String3", …… "StringN") AS Alias_Name;  

语法3：

SELECT MAKE_SET(bits, "Character_1", "character_2", "Character_3", ……., "Character_N") AS Alias_Name; 

二、SQL MAKE_SET 函数 示例

示例 1：以下查询使用带有字符串列表的 MAKE_SET 函数：

SELECT MAKE_SET( 1, ''H'', ''I'', ''A'', ''P'', ''Q'', ''S'', ''R'', ''T'', ''V'', ''M'' ) AS Value_at1st_bit;

输出结果为：

Value_at1st_bit
H

示例 2：以下查询在第 1 位和第 4 位搜索字符串：

SELECT MAKE_SET(1 | 4, ''New'', ''Delhi'', ''is'', ''the'', ''Capital'', ''of'', ''India'') AS Value_at1st_4th_bit;  

输出结果为：

Value_at1st_4th_bit
New, is

示例 3：以下查询显示给定集合中第二位的值：

SELECT MAKE_SET( 2, ''H'', ''I'', ''V'', ''M'' ) AS Value_at2nd_bit;  

输出结果为：

Value_at2nd_bit
I

示例 4：以下查询显示给定集合中第二位和第四位的值：

SELECT MAKE_SET( 2 | 4, ''H'', ''I'', ''A'', ''P'', ''Q'', ''S'', ''R'', ''T'', ''V'', ''M'' ) AS Value_at2_4_bit;  

输出结果为：

Value_at2_4_bit
I, A

示例 5：此示例对结构化查询语言中的表使用 MAKE_SET 函数。

在第五个示例中，我们将创建新表，通过该表我们将使用表值执行 MAKE_SET 函数：

以下块显示了在 SQL 中创建新表的语法：

CREATE TABLE Name_of_New_Table  
(  
First_Column_of_table Data Type (character_size of First Column),    
Second_Column_of_table Data Type (character_size of the Second column ),    
Third_Column_of_table Data Type (character_size of the Third column),    
........,    
Last_Column_of_table Data Type (character_size of the Last column)  
);   

以下 CREATE 语句创建Fresher_Marks表：

CREATE TABLE Fresher_Marks  
(  
Fresher_ID INT PRIMARY KEY,    
First_Name VARCHAR (100),    
Middle_Name Varchar(120),  
Last_Name VARCHAR (200),   
City Varchar(120),  
Aptitude_Marks INT,   
Reasoning_Marks INT,   
Technical_Marks INT,  
Percentage INT  
);  

下面的 INSERT 语句在Fresher_Marks表中插入带有标记和详细信息的新生记录：

INSERT INTO Fresher_Marks (Fresher_ID, First_Name, Middle_Name, Last_Name, City, Aptitude_Marks, Reasoning_Marks, Technical_Marks, Percentage) VALUES (501, Vinay, Roy, Gupta, Lucknow, 85, 92, 78, 85 );  
  
INSERT INTO Fresher_Marks (Fresher_ID, First_Name, Middle_Name, Last_Name, City, Aptitude_Marks, Reasoning_Marks, Technical_Marks, Percentage) VALUES (502, Monu, Roy, Singhania, Chandigarh, 54, 68, 98, 88 );  
  
INSERT INTO Fresher_Marks (Fresher_ID, First_Name, Middle_Name, Last_Name, City, Aptitude_Marks, Reasoning_Marks, Technical_Marks, Percentage) VALUES (504, Ravi, Roy, Kumar, Lucknow, 71, 82, 69, 71 );  
  
INSERT INTO Fresher_Marks (Fresher_ID, First_Name, Middle_Name, Last_Name, City, Aptitude_Marks, Reasoning_Marks, Technical_Marks, Percentage) VALUES (507, Shyam, Roy, Sharma, Delhi, 85, 90, 68, 78 );  
  
INSERT INTO Fresher_Marks (Fresher_ID, First_Name, Middle_Name, Last_Name, City, Aptitude_Marks, Reasoning_Marks, Technical_Marks, Percentage) VALUES (510, Abhay, Kumar, Gupta, Chandigarh, 45, 68, 82, 78);  
  
INSERT INTO Fresher_Marks (Fresher_ID, First_Name, Middle_Name, Last_Name, City, Aptitude_Marks, Reasoning_Marks, Technical_Marks, Percentage) VALUES (509, Riya, Roy, Sharma, Delhi, 68, 90, 69, 91 );  
  
INSERT INTO Fresher_Marks (Fresher_ID, First_Name, Middle_Name, Last_Name, City, Aptitude_Marks, Reasoning_Marks, Technical_Marks, Percentage) VALUES (505, Vishal, Kumar, Sharma, Mumbai, 75, 65, 88, 75 );  

以下 SELECT 语句显示上述Fresher_Marks表的插入记录：

SELECT * FROM Fresher_Marks;   

输出结果为：

Fresher_ID	First_Name	Middle_Name	Last_Name	City	Aptitude_Marks	Reasoning_Marks	Technical_Marks	Percentage
501	Vinay	Roy	Gupta	Lucknow	85	92	78	85
502	Monu	Roy	Singhania	Chandigarh	54	68	98	88
504	Ravi	Roy	Kumar	Lucknow	71	82	69	71
507	Shyam	Roy	Sharma	Delhi	85	90	68	78
510	Abhay	Kumar	Gupta	Chandigarh	45	68	82	78
509	Riya	Roy	Sharma	Delhi	68	90	69	91
505	Vishal	Kumar	Sharma	Mumbai	75	65	88	75

查询 1：以下 SELECT 查询将 MAKE_SET 函数与上述 Fresher_Marks 表的 First_Name、Middle_Name、Last_Name 列一起使用：

SELECT First_Name, Middle_Name, Last_Name, MAKE_SET(2, First_Name, Middle_Name, Last_Name) AS Value_at_2bit FROM Fresher_Marks;

此查询显示上表中每个新生的中间名的值。

输出结果为：

First_Name	Middle_Name	Last_Name	Value_at_2bit
Vinay	Roy	Gupta	Roy
Monu	Roy	Singhania	Roy
Ravi	Roy	Kumar	Roy
Shyam	Roy	Sharma	Roy
Abhay	Kumar	Gupta	Kumar
Riya	Roy	Sharma	Roy
Vishal	Kumar	Sharma	Kumar

查询 2：以下 SELECT 查询将 MAKE_SET 函数与上述 Fresher_Marks 表中 Fresher_ID 大于 502 的学生的 Aptitude_Marks、Reasoning_Marks 和 Technical_Marks 列一起使用：

SELECT Fresher_ID, Aptitude_Marks, Reasoning_Marks, Technical_Marks, MAKE_SET(4, Aptitude_Marks, Reasoning_Marks, Technical_Marks) AS Value_at_4bit FROM Fresher_Marks WHERE Fresher_ID > 502;  

输出结果为：

Fresher_ID	Aptitude_Marks	Reasoning_Marks	Technical_Marks	Value_at_4bit
504	71	82	69	69
507	85	90	68	68
510	45	68	82	82
509	68	90	69	69
505	75	65	88	88

查询 3：以下 SELECT 查询将 MAKE_SET 函数与上述 Fresher_Marks 表的 First_Name、Middle_Name、Last_Name 列一起使用：

SELECT First_Name, Middle_Name, Last_Name, MAKE_SET(1 | 3, First_Name, Middle_Name, Last_Name) AS Value_at_1_3bit FROM Fresher_Marks;  

此查询显示上表中每个新生的中间名的值。

输出结果为：

First_Name	Middle_Name	Last_Name	Value_at_1_3bit
Vinay	Roy	Gupta	Vinay, Roy
Monu	Roy	Singhania	Monu, Roy
Ravi	Roy	Kumar	Ravi, Roy
Shyam	Roy	Sharma	Shyam, Roy
Abhay	Kumar	Gupta	Abhay, Kumar
Riya	Roy	Sharma	Riya, Roy
Vishal	Kumar	Sharma	Vishal, Kumar