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I have a table of Invoice with different Invoices. Each Invoice has a unique Invoice Number and an amount value. Invoices are of two type. One is of Invoice Type, and the other is of Settled type. If there's a invoice created, the entry in the table will be of invoice type, the amount will be in positive. If the user paid that invoice, another entry with the same invoice number will be entered in the table but with the negative amount because the user has paid that amount.I have a table of Invoice with different Invoic