I want to calculate the opportunity / lead conversion rate. I have the following code:  My problem is in the form of pivot field percent, which is not calculated as properly as on pgadmin. . someone help me, i'm very thanks

def _select(self):
    select_str = super(OpportunityReport, self)._select()
    select_str += """,
                            c.x_mien AS x_mien,
                            c.group_id AS group_id,
                            c.brand_id AS brand_id,
                            c.x_trangthai_lead AS x_trangthai_lead,
                            c.x_phanloai_lead AS x_phanloai_lead,
                            c.customer_care AS customer_care,
                            count(c.type) as lead,
                            sum(CASE WHEN c.type = 'opportunity' THEN 1 ELSE 0 END) AS opportunity,
                            (100 * sum(CASE WHEN c.type = 'opportunity' THEN 1 ELSE 0 END))/count(*) as percent
                     """
    return select_str

def _group_by(self):
    group_by_str = super(OpportunityReport, self)._group_by()
    group_by_str += """,
                              c.x_mien,
                              c.group_id,
                              c.brand_id,
                              c.x_trangthai_lead,
                              c.x_phanloai_lead,
                              c.customer_care
                        """
    return group_by_str

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