Question

我有一个带有firstname，middlename，lastname的表。我想将这3列数据作为全名添加到一个中，就像中间名一样！=＆＃39;＆＃39;那么fullname = firstname middlename和if lastname！=＆＃39;＆＃39;然后fullname = firstname middlename lastname。我尝试如下，但没有行受到影响。

UPDATE studentprofiles SET fullname = CASE middlename WHEN middlename !=  '' THEN firstname +  ' ' + middlename ELSE firstname END WHERE fullname = ''

怎么做？我必须更新多行。欢迎任何帮助/建议。

Answer 1

您是否尝试使用AND这样的内容：

CASE
WHEN middlename != '' AND lastname != '' THEN firstname + middlename + lastname
ELSE ''
END AS fullname

Answer 2

问题解决如下：

UPDATE studentprofiles 
    SET fullname = CASE
                WHEN middlename != '' AND lastname != '' THEN concat(firstname,' ',middlename,' ',lastname)
                WHEN middlename != '' AND lastname = '' THEN concat(firstname,' ',middlename)
                WHEN middlename = '' AND lastname != '' THEN concat(firstname,' ',lastname)
                ELSE concat(firstname)
END

Answer 3

为什么不能简单地连接列数据，如

UPDATE studentprofiles 
SET fullname = concat(firstname, middlename, lastname);

编辑：在这种情况下，您可以使用IFNULL()功能

UPDATE studentprofiles 
SET fullname = IFNULL(firstname,'') +
               IFNULL(middlename, '') +
               IFNULL(lastname, '');

Answer 4

尝试使用它：

CASE case_value
    WHEN when_value THEN statement_list
    [WHEN when_value THEN statement_list] ...
    [ELSE statement_list]
END CASE

查看此链接以获取更多信息 enter link description here

如何使用mysql中的case语句将3列数据合并为一列

4 个答案: