I have two variables which are comma separated lists. I would like to join these two variables by appending the lines based on their unique id. 

Example below:

```
var1="
id1,data1,data2,data3
id2,data1,data2,data3
id3,data1,data2,data3
id4,data1,data2,data3
"

var 2="
id1,data4,data5,data6
id2,data4,data5,data6
id3,data4,data5,data6
id4,data4,data5,data6
"

output="
id1,data1,data2,data3,data4,data5,data6
id2,data1,data2,data3,data4,data5,data6
id3,data1,data2,data3,data4,data5,data6
id4,data1,data2,data3,data4,data5,data6
"

```

I'm not the best at AWK and while I can decrypt it I still have troubles coming up with commands. If you could help that would be great!