SQL REVERSE 字符串函数

一、SQL REVERSE 字符串函数 语法

SQL 中的 REVERSE 字符串函数以相反的顺序返回字符串。它在查询输出的第一个位置显示字符串的最后一个字符，在最后一个位置显示第一个字符。

语法1：此语法使用带有 SQL 表的列名的 REVERSE 函数：

SELECT REVERSE (Column_Name) AS Alias_Name FROM Table_Name;

在语法中，我们必须指定要运行 REVERSE 函数的列的名称。

语法2：此语法使用带有字符串的 REVERSE 函数：

SELECT REVERSE (Original_String);  

二、SQL REVERSE 字符串函数 示例

示例 1：以下 SELECT 查询反转给定的字符串：

SELECT REVERSE (  '          YIIDIAN');  

输出结果为：

'NAIDIIY          '

示例 2：以下 SELECT 查询以相反的顺序显示给定的字符串：

SELECT REVERSE (  'NEW DELHI IS THE CAPITAL OF INDIA');  

输出结果为：

'AIDNI FO LATIPAC EHT SI IHLED WEN'

示例 3：以下 SELECT 查询以相反的方式显示数字字符串：

SELECT REVERSE (  '578442297425');  

输出结果为：

524792244875

示例 4：此示例对结构化查询语言中的表使用 REVERSE 函数。

首先，我们必须创建新的 SQL 表，这有助于理解 REVERSE 字符串函数。在 SQL 数据库中创建新表的语法如下：

CREATE TABLE table_name  
(  
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Employee_Grade表：

CREATE TABLE Employee_Grade  
(  
Employee_ID INT PRIMARY KEY,    
First_Name VARCHAR (100),    
Last_Name VARCHAR (100),   
First_City Varchar(120),  
Second_City Varchar(120),  
New_City Varchar(120),  
Attendance_Remarks INT,   
Work_Remarks INT,   
Grade Varchar (80)  
);  

下面的 INSERT 语句在Employee_Grade表中插入员工的成绩和备注记录：

INSERT INTO Employee_Grade (Employee_ID, First_Name, Last_Name, First_City, Second_City, New_City, Attendance_Remarks, Work_Remarks, Grade) VALUES (10, Ramesh, Sharma, Lucknow Aurangabad, Ghaziabad, 88, 95, A2);  
  
INSERT INTO Employee_Grade   
(Employee_ID, First_Name, Last_Name, First_City, Second_City, New_City, Attendance_Remarks, Work_Remarks, Grade)   
VALUES ( 02, Yadu, Sharma, Aurangabad, Ghaziabad, Noida, 95, 82, A1 );  
  
INSERT INTO Employee_Grade   
(Employee_ID, First_Name, Last_Name, First_City, Second_City, New_City, Attendance_Remarks, Work_Remarks, Grade)   
VALUES (07, Vijay, Ramna, Noida, Ghaziabad, Lucknow, 91, 95, A1);  
  
INSERT INTO Employee_Grade   
(Employee_ID, First_Name, Last_Name, First_City, Second_City, New_City, Attendance_Remarks, Work_Remarks, Grade)    
VALUES (04, Bhanu, Rangopalr, Ghaziabad, Noida, Lucknow, 85, 82, A2);  
  
INSERT INTO Employee_Grade   
(Employee_ID, First_Name, Last_Name, First_City, Second_City, New_City, Attendance_Remarks, Work_Remarks, Grade)   
VALUES (11, Harry, Roy, Noida, Kanpur, Ghaziabad, 95, 97, A1);  
  
INSERT INTO Employee_Grade   
(Employee_ID, First_Name, Last_Name, First_City, Second_City, New_City, Attendance_Remarks, Work_Remarks, Grade)   
VALUES (16, Akash, Ramna, Ghaziabad, Meerut, Aurangabad, 95, 90, B1);  
  
  
INSERT INTO Employee_Grade   
(Employee_ID, First_Name, Last_Name, First_City, Second_City, New_City, Attendance_Remarks, Work_Remarks, Grade)   
VALUES (19, Ram, Ramna, Lucknow, Ghaziabad, Aurangabad, 89, 95, A2);  

以下 SELECT 语句显示上述Employee_Grade表的插入记录：

SELECT * FROM Employee_Grade;   

输出结果为：

Employee_ID	First_Name	Last_Name	First_City	Second_City	New_City	Attendance_Remarks	Work_Remarks	Grade
10	Ramesh	Sharma	Lucknow	Aurangabad	Ghaziabad	88	95	A2
02	Yadu	Sharma	Aurangabad	Ghaziabad	Ghaziabad	95	82	A1
07	Vijay	Ramna	Noida	Ghaziabad	Lucknow	91	95	A1
04	Bhanu	Rangopalr	Ghaziabad	Noida	Lucknow	85	82	A2
11	Harry	Roy	Noida	Kanpur	Ghaziabad	95	97	A1
16	Akash	Ramna	Ghaziabad	Meerut	Aurangabad	95	90	B1
19	Ram	Ramna	Lucknow	Ghaziabad	Aurangabad	89	95	A2

查询 1：以下 SELECT 查询对上述 Employee_Grade 表的 First_Name 列使用 REVERSE 函数：

SELECT First_Name, REVERSE(First_Name) AS REVERSE_FirstName FROM Employee_Grade;  

此语句以相反的顺序显示名字的所有值。

输出结果为：

First_Name	REVERSE_FirstName
Ramesh	hsemaR
Yadu	udaY
Vijay	yajiV
Bhanu	unahB
Harry	yrraH
Akash	hsakA
Ram	maR

查询 2：以下 SELECT 查询对上述 Employee_Grade 表的 Last_Name 列使用 REVERSE 函数：

SELECT Last_Name, REVERSE(Last_Name) AS REVERSE_LastName FROM Employee_Grade;  

此语句以相反的顺序显示姓氏的所有值。

输出结果为：

Last_Name	REVERSE_LastName
Sharma	amrahS
Sharma	amrahS
Ramna	anmaR
Rangopalr	rlapognaR
Roy	yoR
Ramna	anmaR
Ramna	anmaR

查询 3：以下 SELECT 查询对上述 Employee_Grade 表的 First_City 和 New_City 列使用 REVERSE 函数：

SELECT First_City, REVERSE(First_City) AS REVERSE_FirstCity, New_City, REVERSE(New_City) AS REVERSE_NewCity FROM Employee_Grade;  

此 SQL 语句以相反的顺序显示 First_City 和 New_City 的所有城市。

输出结果为：

First_City	REVERSE_FirstCity	New_City	REVERSE_NewCity
Lucknow	wonkcuL	Ghaziabad	dabaizahG
Aurangabad	dabagnaruA	Ghaziabad	dabaizahG
Noida	adioN	Lucknow	wonkcuL
Ghaziabad	dabaizahG	Lucknow	wonkcuL
Noida	adioN	Ghaziabad	dabaizahG
Ghaziabad	dabaizahG	Aurangabad	dabagnaruA
Lucknow	wonkcuL	Aurangabad	dabagnaruA