Question

I have two MySQL tables:

  Table items            Table buffer
---------------         -------------
id     keywords         id      value
1      val1             1       val2
2      val1             2       val2
3      val1             3       val2

Both keywords and value are VARCHAR(250). Now I want to update all keywords in table items like this:

   Table items
-----------------
id     keywords
1      val1, val2
2      val1, val2
3      val1, val2

I tried to achieve this with CONCAT but obviously I’m doing something wrong. Can you please help me.

Answer 1

You need to UPDATE with JOIN like so:

UPDATE items i
INNER JOIN buffer b ON i.id = b.id
SET i.keywords = CONCAT(i.keywords, ', ', b.value);

SQL Fiddle Demo