[Flask] flask SelectMultipleField save multiselection in database

[licence Uni Spé_-_Administarttion Ds Sys Appl]

HELLO,

I use the *SelectMultipleField *function but when I select several values
in my en form I receive this error which comes from my server* MySQL[
(1241, 'Operand should contain 1 column(s)')]*.

 mat_actif = SelectMultipleField('Materiels :', choices = [
('Port USB','Port USB'),         ('Lecteur CD','Lecteur CD'),
('Aucun','Aucun')],)

in my template i use :

{{ wtf.quick_form(form, form_type='horizontal',
horizontal_columns=('lg', 3, 6)) }}

can you help me please. thank you
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