Pie chart error

Hello!
I am new to ERP. Axelor . when i used bar chart

but when i used pie char

.

This issue is data is not showing like type=bar .

please help me!!!

If in view chart.sale.turnover.by.product.ytd.vs.lastyear

<category key="_year" type="text" title="Year"/>
<series key="_turn_over" type="bar" groupBy="_product" title="TurnOver"/>
</chart>

by

  <category key="_product" type="text" title="Product"/>
  <series key="_turn_over" groupBy="_year" type="donut" title="Turnover"/>
  </chart>

You get that

2 « J'aime »

thank you . it helped me!!!