I have a column with accessories of products as below example:

**TABLE1**

```
ProductID    accessories
1            2,3  
2            1,4,5
3
4            1
5            2

```

It means that for the PRODUCT 2, it has the accessories product ids 1,4 and 5

and i have THE FINAL table 2 below which look like this

**TABLE2**

```
GRP     ProductID     accessories 
a       2             
b       3             
c       1             
d       4             
e       5 

```

so actually if using UPDATE it would be like this

**TABLE2**

```
UPDATE table t2
INNER JOIN table1 t1
On t2.ProductID = t1.ProductID
set t2.accessories = t1.accessories 

GRP     ProductID     accessories
a       2             1,4,5
b       3              
c       1             2,3
d       4             1
e       5             2

```

but i want to change the productIDs in the t2.accessories with the GRP character instead according to the t2.ProductID so that the FINAL table looks like this .

**TABLE2**

```
GRP     ProductID     accessories
a       2             c,d,e
b       3              
c       1             a,b
d       4             c
e       5             a

```

iam really confused how to do that correctly i was able to handle this using php code, but it takes loong time becouse i have 100k products therefore i prefer to use some group\_concat or concat\_ws to handle this

and some t2.accessories may already be stored, therefore it should be distinct values, so there is no duplicate t2.accessories on table2

Here is the tables <http://sqlfiddle.com/#!9/bfddf>