Question

如果在client_name后面有方括号，则尝试显示client_nickname，但是，如果client_nickname为NULL，则仍显示client_name。无法显示没有昵称的client_name。

尝试了WHERE语句，但仍仅显示带有昵称的名称。

this is a dummy database i created randomly

CREATE TABLE client ( 
client_id INT(6) UNSIGNED AUTO_INCREMENT PRIMARY KEY, 
firstname VARCHAR(30) NOT NULL, 
lastname VARCHAR(30) NOT NULL, 
client_nickname VARCHAR (30),
client_mobile int(10), 
client_home int(10),
client_office int(10)
); 

INSERT INTO client (client_id, firstname, lastname, client_nickname, client_mobile, client_home, client_office) 
VALUES ('1', 'Doe', 'John', 'Johnny', '11223344',NULL, '66778899'); 
INSERT INTO client (client_id, firstname, lastname, client_nickname, client_mobile, client_home, client_office) 
VALUES ('2', 'Mary', 'Lee', NULL, '99887766','44556677', '66778899'); 
INSERT INTO client (client_id, firstname, lastname, client_nickname, client_mobile, client_home, client_office) 
VALUES ('3', 'Dreylan', 'Zhou', 'LilMonster', NULL, NULL, '66770000');

The code I worked out so far to achieve what i want

SELECT CONCAT (firstname, " ", lastname, ' (', client_nickname, ')') AS client_name
FROM client;

我希望列“ client_name”中包含所有3个这样的客户端名称：

Doe John (Johnny)
Mary Lee
Dreylan Zhou (LilMonster)

但实际输出仅为：

Doe John (Johnny)
Dreylan Zhou (LilMonster)

Answer 1

您是否需要检查null

SELECT case when  client_nickname is null  
          then CONCAT(firstname, " ", lastname)
          else  CONCAT(firstname, " ", lastname, ' (', client_nickname, ')')
        end AS client_name
FROM client;

MySQL-如何在名字后面显示昵称（如果有，则只是名字）？

1 个答案: