MySQL UPDATE将数据附加到列中

I need to UPDATE tablename (col1name)

我需要UPDATE tablename（col1name）

If there is already data, I need to append it with values 'a,b,c' If it is NULL, I need to add the values 'a,b,c'

如果已有数据，我需要用值'a，b，c'附加它如果它是NULL，我需要添加值'a，b，c'

I know there is a CONCAT argument, but not sure what the SQL syntax would be.

我知道有一个CONCAT参数，但不确定SQL语法是什么。

update tablename set col1name = concat(ifnull(col1name, 'a,b,c'), 'a,b,c')

update tablename set col1name = concat（ifnull（col1name，'a，b，c'），'a，b，c'）

Is the above correct?

以上是正确的吗？

4 个解决方案

#1

Try this Query:

试试这个查询：

update tablename set col1name = concat(ifnull(col1name,""), 'a,b,c');

Refer this sql fiddle demo.

请参阅此sql小提琴演示。

#2

This should do it:

这应该这样做：

update tablename set
col1name = if(col1name is null, 'a,b,c', concat(col1name, 'a,b,c'));

Or you could make your life easier by doing it in two steps:

或者您可以通过两个步骤来简化您的生活：

update tablename set col1name = '' where col1name is null;

then

然后

update tablename set col1name = concat(col1name, 'a,b,c');

#3

You can use the following:

您可以使用以下内容：

update yourtable 
set yourcol = case when yourcol is null then 'a,b,c'
                  else concat(yourcol, ' a,b,c') end

See SQL Fiddle with Demo

请参阅SQL Fiddle with Demo

Sample data:

样本数据：

CREATE TABLE yourtable(`yourcol` varchar(50));

INSERT INTO yourtable(`yourcol`)
VALUES  ('sadsdh'),
    (NULL);

Will return:

将返回：

|      YOURCOL |
----------------
| sadsdh a,b,c |
|        a,b,c |

#4

IFNULL(column,''), saves any if statements, makes the SQL much simpler!

IFNULL（列，''）保存任何if语句，使SQL更简单！

MySQL 5.6 Schema Setup:

MySQL 5.6架构设置：

CREATE TABLE tablename
    (`yourcol` varchar(50))
;

INSERT INTO tablename
    (`yourcol`)
VALUES
    ('sadsdh'),
    (NULL)
;

UPDATE tablename SET
    yourcol = CONCAT( IFNULL(yourcol,' '), 'somevalue' )
;

Query:

查询：

select *
from tablename

Results:

结果：

|         yourcol |
|-----------------|
| sadsdhsomevalue |
|       somevalue |

#1