thanks for your answer, but I don't understanf very well th code.
to explain my problem with picture of sample of project :
when I use in my code the string variable start_date and end_date , like in the picture below
I have error,
but if I use the date in string format like '1-12-2019' and '28-12-2019' in the source code at line 10, I have a display of the content of database, and at this case the date block is imperatively not used.
the display is correct for me :
and at the bottom there is the pushbutton to activate the function select_by_dates
to explain my problem with picture of sample of project :
when I use in my code the string variable start_date and end_date , like in the picture below
I have error,
but if I use the date in string format like '1-12-2019' and '28-12-2019' in the source code at line 10, I have a display of the content of database, and at this case the date block is imperatively not used.
the display is correct for me :
and at the bottom there is the pushbutton to activate the function select_by_dates