Question

我有x桌。

x
............
id    email      first_name   last_name
'''''''''''''''''''''''''''''''''''''''
 1  a@gmail.com  Martin        Robert
 2  b@gmail.com     
 3  c@gmail.com  Sam           Anderson

我正在使用以下查询，输出为：

 select id, CONCAT(first_name, ' ', last_name) from a;

 The output is
 .......................................
 id    CONCAT(first_name, ' ', last_name)
 '''''''''''''''''''''''''''''''''''''''
  1    Martin Robert
  2
  3    Sam Anderson

我想忽略CONCAT（）中first_name和last_name都为空的行。

我的输出如下

  .......................................
 id    CONCAT(first_name, ' ', last_name)
 '''''''''''''''''''''''''''''''''''''''
  1    Martin Robert
  3    Sam Anderson

谢谢。

Answer 1

这种方式：

select id, CONCAT(first_name, ' ', last_name) from a where first_name is not null and last_name is not null;

Answer 2

您需要where子句

假设空值表示空值

 select id, CONCAT(first_name, ' ', last_name) 
 from a 
 where ifnull(first_name,'') = '' 
 and ifnull(last_name,'') =  '';

或者为了测试也为空字符串

{{1}}

Answer 3

SELECT ID, CONCAT(FIRST_NAME, ' ', LAST_NAME)
FROM TABLE_NAME_A
WHERE FIRST_NAME IS NOT NULL
AND LAST_NAME IS NOT

Answer 4

尝试此操作，它必须适合您的情况：

SELECT id, CONCAT(first_name, ' ', last_name) as fullname 
FROM YOUR_TABLE_NAME 
WHERE first_name != "" AND last_name != "";

从表中选择字段-MYSQL JOIN

4 个答案: