MySQL 中的 RIGHT()函数

原文:https://www.geeksforgeeks.org/right-function-in-mysql/

RIGHT ()函数在 MySQL 中用于从给定字符串的右侧提取指定数量的字符。第二个参数用于决定它应该返回多少个字符。

语法:

RIGHT( str, len )

参数:该函数接受两个参数，如上所述，如下所述:

  • String: A given string from which multiple characters are to be extracted from the right.
  • len : the number of characters to be extracted. If this parameter is greater than the number of characters in the string, this function will return the actual string.

返回:它从一个字符串中返回多个字符(从右开始)。

示例-1 : 将右()函数应用于给定的字符串。

SELECT RIGHT("geeksforgeeks", 4) AS Right_Str;

输出: T2T4

右 _ Str

示例-2 : 将右()函数应用于数字。

SELECT RIGHT(12345678, 4) AS Right_Num;

输出:T5】

右 _ Num
5678

示例-3 : 在字符串中插入>字符时，对给定字符串应用 RIGHT()函数。

SELECT RIGHT("geeksforgeeks", 20) AS Right_Str;

输出:T5】

右 _ Str
极客暴发户

示例-4 : 应用 RIGHT()函数查找表中玩家的姓氏。为了演示，创建一个名为玩家的表格。

CREATE TABLE Player(

    Player_id INT AUTO_INCREMENT,  
    Player_name VARCHAR(100) NOT NULL,
    Playing_team VARCHAR(20) NOT NULL,
    PRIMARY KEY(Player_id )

);

现在，在玩家表中插入一些数据:

INSERT INTO  
    Player(Player_name, Playing_team)

VALUES
    ('Virat Kohli', 'RCB' ),
    ('Rohit Sharma', 'MI' ),
    ('Dinesh Karthik', 'KKR'  ),
    ('Shreyash Iyer', 'DC'  ),
    ('David Warner', 'SRH' ),
    ('Steve Smith', 'RR'  ),
    ('Andre Russell', 'KKR' ),
    ('Jasprit Bumrah', 'MI' ),
    ('Risabh Panth', 'DC'  ) ;

所以，玩家表是:

mysql> SELECT * FROM Player;
+-----------+----------------+--------------+
| Player_id | Player_name    | Playing_team |
+-----------+----------------+--------------+
|         1 | Virat Kohli    | RCB          |
|         2 | Rohit Sharma   | MI           |
|         3 | Dinesh Karthik | KKR          |
|         4 | Shreyash Iyer  | DC           |
|         5 | David Warner   | SRH          |
|         6 | Steve Smith    | RR           |
|         7 | Andre Russell  | KKR          |
|         8 | Jasprit Bumrah | MI           |
|         9 | Risabh Panth   | DC           |
+-----------+----------------+--------------+

现在我们将找到每个玩家的姓氏，要找到姓氏我们必须应用以下方法-

  • First, use the instr () function to find the position of the space () in the name.
  • Secondly, use the length () function to find the length of the player's name. The "len" of the right function here will be the length of the Player_name minus the position of the'' (space) character.
  • Third, use the right () function to extract the last name of the player.
SELECT 
    Player_name,
    RIGHT(Player_name, LENGTH(Player_name) - INSTR(Player_name, ' ')) Lastname,
    Playing_team
FROM
    Player;

输出:

+----------------+----------+--------------+
| Player_name    | Lastname | Playing_team |
+----------------+----------+--------------+
| Virat Kohli    | Kohli    | RCB          |
| Rohit Sharma   | Sharma   | MI           |
| Dinesh Karthik | Karthik  | KKR          |
| Shreyash Iyer  | Iyer     | DC           |
| David Warner   | Warner   | SRH          |
| Steve Smith    | Smith    | RR           |
| Andre Russell  | Russell  | KKR          |
| Jasprit Bumrah | Bumrah   | MI           |
| Risabh Panth   | Panth    | DC           |
+----------------+----------+--------------+

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