Seems to be working fine for me (using JMP16.2 Pro on Windows 10).
dt = Current Data Table();
dt << Select Where(:age == 12);
d3 = dt << Subset(Output table("a12", Selected Rows(1), Selected Columns(0)));
![jthi_0-1648280947050.png jthi_0-1648280947050.png](https://community.jmp.com/t5/image/serverpage/image-id/41172i65F470E34514E00F/image-size/medium?v=v2&px=400)
![jthi_1-1648280965780.png jthi_1-1648280965780.png](https://community.jmp.com/t5/image/serverpage/image-id/41173iFE31CEA2077E5DB3/image-size/medium?v=v2&px=400)
You seem to be missing : from the column name, maybe Toolbar is more strict on the syntax? At least if I remove that from the toolbar script I will get this error:
![jthi_2-1648281050586.png jthi_2-1648281050586.png](https://community.jmp.com/t5/image/serverpage/image-id/41174iC3CB5CBECE6CBD2A/image-size/medium?v=v2&px=400)
but it will work fine from script editor (in my opinion it shouldn't)
-Jarmo