MySQL UPDATE append data into column

Question

I need to 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\'

I

Answer 1

You can use the following:

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

Sample data:

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

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

Will return:

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

Answer 2

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

MySQL 5.6 Schema Setup:

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

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

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

Query:

select *
from tablename

Results:

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

Answer 3

why are you write ifnull function: it is obvious that if col1name1 is empty it concatenate to null means null+'a,b,c' simply 'a,b,c' set col1name = concat(ifnull(col1name,""), 'a,b,c') instead of this you can directly write set col1name = concat(col1name, 'a,b,c')

Answer 4

Try this Query:

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

Refer this sql fiddle demo.

Answer 5

This should do it:

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:

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

then

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