No Valid Fields in Y-axis where crate visualization

Hi, I have a simple oracle table, and want to make a visualization line.

Here is the table:

      CREATE TABLE "user"."T_NET_ONLINE" 
    (	"TIMESTAMP" DATE, 
    "ONLINEUSER" VARCHAR2(20 BYTE)
     ) 

And I started with ‘Write a SQL’, the sql like this:

select * from t_net_online

Very simple, and got the result.

But when I click visualization, chose line, I can only select X-axis, but no valid fields in Y-axis.

image

So, how the problem happen?

Thanks a lot.

BTW, I tried in Ask a question->Simple Question, and choose the table, this time Y-axis can choose ONLINEUSER in my table.

Is there any difference in the two way?

Hi @baalchina
What’s the Field Type of ONLINEUSER? Admin > Data Model > (database) > (table) > (column) :gear:
There’s a couple of issues open about VARCHAR2, so perhaps it’s related to that:
https://github.com/metabase/metabase/issues?q=is%3Aissue+is%3Aopen+VARCHAR2

This happens when you use a field that Metabase can't 'count'. For example, you may have a varchar column but it has numbers in it. Change the number column to an int or decimal and it will work.

Same goes for dates.